[Formulajones]

Of course none of us can speak for Rick or Scott, but since that car was purpose built to race the stock class (and this year was chosen on purpose just for that reason, and others) I'd bank on it being a featherweight, like I mentioned, if it were over 3200 without a driver I'd be shocked. It's a big reason why it runs so good. That's just an educated guess on my part based on what I've seen and owned myself.

[Formulajones]

To be top dog at the pure stock or the factory stock races I believe the L88 still holds the record. Might be Julie Pennington's car but not sure, there are a handfull of L88's that run so hard to say who has it now. Didn't take people long to realize L88's are an ideal overall package for a dozen reasons. I know once they got below roll bar requirement (11.49) they were told to slow down, lol.

http://www.youtube.com/watch?feature...&v=Z2dW8ToImLs

[rexs73gto]

I thought that all the vetts were scaled at 3200 lbs & no more as that why each year took so long for them to come out.. One of the rules when they were making the vetts were that they couldn't be more then 3200 lbs or they had to be redesigned. I read that some where as that was one of Zora D's rules for the vette. He want always for the car to be no more then that to be competitive in the race circles.

[2manyT/A'S]

Originally Posted by Formulajones

Here I found an old glossy running my car. I remember this race and the car in the other lane, but don't remember the year exactly.
The 97 bird is a procharged LT1 that should be making twice the power I am. My stocker put a hurt on him The firts 60 foot was everything, this is about mid track trying to run me down, he didn't get it done. The race was at Kil-Kare back when the TA Nats used to have drag racing and made it worthwhile going.. Several people enjoyed watching my bird run and one of them shot this photo. Somehow they got in touch with other people that knew me and a few weeks later this photo was in my mailbox. I thought that was pretty cool. Enjoy, photobucket won't keep it up for long....

Alright.....give us the lowdown....

[Formulajones]

I'll let out some tricks I did. I didn't however exploit the rules to the full extent because this was still primarily a street driven car (and still is).

I didn't go with the allowable 1.5 compression bump or the max allowable bore either, and elected to keep this a pump gas motor. So it's right on the edge, although finicky, so I mix 3-4 gallons of race gas on race day to be safe. Pump gas on the street.

.030 over with a forged TRW flat top that is NHRA legal (hence legal in pure stock as well per rules) and assentially isn't any real difference from the factory flat tops. Block is zero decked. Standard ring package used. So again I didn't exploit the rules here which actually allow the much thinner (ie: less friction and weight) 1/16" ring package if you wish. That's how most aftermarket pistons come nowadays anway.
I wanted durability and long lasting, that was the thought process, so the standard "thick" ring package was used.

Heads are bone stock 1970 ram air III castings (no porting allowed) They were milled .010 to ensure flatness and a good seal. Afterwards they CC'd at 74. Stock OEM valves used, nothing necked down for flow or anything fancy like that. All new seats and guides, springs etc...Only deviation from stock is a nice multiangle valve job, which is allowed per rules. Compression came in at 10:1.

Camshaft is stock melling blueprint ram air III. Melling at the time had more accurate lobe profiles and was the favorite among the pontiac guys years ago. Only deviation in the valvetrain is BBC rocker studs (larger diameter for more stability, not that important however with stock spring pressures) but more importantly I gain complete adjustability and can set preload. Camshaft is installed advanced to increase cylinder pressure and give me a slight boost in low end torque (you'll see why in a minute)
Intake, carb, distributor, manifolds, all stock correct casting numbers.

Trans and rear have never been out of the car. 400 turbo, stock 40+ year old everything and never rebuilt. Stock 12 bolt and 3.31 gears. More gear allowed but again, primarily a street car so I gave up some ET, Car could use 3.73's. Cam advanced for a little more grunt to get the car moving with the mild gear.
All stock springs and shocks (oil filled shocks on the front for more movement) and front sway bar frame mounts spaced down slightly so as not to crush the bar with the bushings to allow the bar to move freely, however still hooked up per rules. Pinion angle shimmed and set to 4*, to give zero angle under load for best transfer of HP. All stock original 40 year old suspension bushings that are in fine shape but "broken in ". That's really it for suspension tricks and as you can see from the pics, the car is effective at transfering weight to the wheels and hooks up nicely, a breeze to drive on stock rubber.
Exhaust is the allowable 2 1/2 inch setup with a stock style transverse muffler as the rules state.
Lots of tuning on dyno with a wideband and tweaking at the track, makes 301/355 at the rear wheels.

I gave up HP on the engine build for streetability, and didn't exploit many tricks. Engine built 16+ years ago and still running as the day it was built some 50,000 miles later. Not raced much in the last several years however.

[Jack Ferris]

Originally Posted by 70RAlll

I get a kick out of that youtube link. Ricks RAll dyno'd at 525 hp , pretty stout for a stock built 400. I built and tuned his quadrajet that is running that car,sight unseen with no changes needed when dyno'd,which is how I know these numbers. Really humors me to see that link on PY's, wasn't long ago someone told me to "shut up and learn about carbs from those that know" on a PY thread discussing an EES 70 Q Jet.. now one of my carbs running one of the fastest Pontiacs out there is linked on a PY thread.. funny...yes, funny..

I just gots to know how a "stock" RAll 400 is making 525 hp.
Im not hatin, Im not out to prove anybody wrong or rattle stones, I just would like to know how that happens. Using basic headflow calculations this motor would have to be somewhere around 120% VE to product that power. Not saying it is impossible, I just want to know how its done with the "stock" parts being used. I know RAll heads are indeed unique in the way they have almost equal airflow in the intake and exhaust ports. Is this why?

To run 11.50 at 3400# takes roughly 440 hp. To run 122 mph takes around 480 hp

So, this particular car making 525 hp in excellent air should run in the mid 10.80's at close to 126 mph.

Pretty impressive I'd say.

[Formulajones]

Well, not to knock down HP numbers but they all have to be taken with a grain of salt.

The type of dyno wasn't mentioned, the brand, the method of testing, the correction factor etc....

All these things have an affect on the numbers.

Some things I can tell you, that number if indeed correct, was likely done in an engine dyno cell before installed in the car. Again not knowing the brand (DTS is one I'm familiar with and they are stingy) and not knowing the setup, some dyno's won't allow testing with stock exhaust manifolds. They lack the room, so sometimes specifically made dyno headers are used, which actually make more power than chassis headers do. That's just one scenario.

Another could be that the engine was run with no accessories, no mechanical water pump, no mechanical fuel pump etc...which is common to ease hook up and speed up the dyno process. In which case you could see a 20-40 HP bump.

Without knowing any of these things it's too difficult to judge.

Dyno's are tuning tools more than anything, the number is just a guideline. On any different dyno or operator the numbers could be different, as much as 25HP.

To make that kind of power the heads would only need to flow about 260 cfm with alot of other factors that play a roll.

With the rules that allows a 1.5 bump in advertised compression and this car being purposely built to run the class, you can bet you're looking at a 12.25:1 engine, and probably a max bore of .070 would also help to increase the head flow by unshrouding the valves. From there it's attention to detail. Things like zero decking the block, CC the heads and make sure all chambers are identical, making sure all rocker arms are the advertised ratio, checking cam lobes, degreeing the camshaft, the small 1/16" ring package helps, and just lots of other little things that a good engine builder will do, even on a stock type rebuild using stock parts to extract the most out of what you have.

Keep in mind none of these cars actually had the compression ratio advertised from the factory, and that goes for any OEM engine back then. Most fell .25 to .50 a point below advertised, since the pistons were generally .020 to .025 down in the hole, and cylinder heads CC all over the place, you have core shift issues with cast parts, intake manifolds that don't match up very well (pontiac is notorious for that), deck heights that vary from front to back from core shift which also affects compression ratios from one end of the engine to the other. Etc....
All these things are corrected (or should be) even during your most basic rebuilds, so in essence when finished it should run better than it ever did from the factory because you are correcting mass produced issues that weren't a concern back then. A well done stock rebuild will boost the HP without any real tricks.

[transam1972]

how much did the original round port Ram Air II heads evolve to RA IV, then 455 H.O.?...minor or big changes..thanks!!

[Formulabruce]

Originally Posted by Formulajones

I didn't go with the allowable 1.5 compression bump

Block is zero decked.

Heads are bone stock 1970 ram air III castings (no porting allowed) They were milled .010 to ensure flatness and a good seal. Afterwards they CC'd at 74. Compression came in at 10:1.
Camshaft is installed advanced to increase cylinder pressure and give me a slight boost in low end torque (you'll see why in a minute)

Breaking this down a bit....having done this same thing before.... Don't take offense, just trying to justify your results..
1. Seems the CR did get bumped.. which IS logical in this build.
2. Decking the block , Read below a bit from Jim hand on how Both decking and lowering timing because of it, can and does change the CR.
3. Heads. Stock heads are 72 cc, how does one slice off 10K and get 74 cc?
4. Advancing cam to "increase cylinder pressure" >> Fact>> Does Increase the CR....
Im NOT being critical, just stating that what you did do had a huge effect on performance which deviated alot from stock. ( I do like it, I did it, and I didnt like the CR at "dynamic" of 10.5) but I wasnt drag racing it much.
Read some of Jim Hands comments on block decking and its effects...
Quote >>Jim Hand "Deck Height or Deck Clearance:

This most important step consists of measuring the distance from the assembled piston tops to the surface of the block deck (deck clearance), and milling as necessary. The general feeling is that the total quench or squish distance should be about .040". The quench distance is the compressed thickness of the head gasket plus the deck clearance. As most of our Pontiac head gaskets compress to about .042", that means we want about 0 deck clearance. The quench area is the flat part of the piston that would contact a similar part of the head if you had .000 assembled quench height. In a running engine, the .040 quench height decreases to a close collision between the piston and the cylinder head. The shock wave from the near collision drives air at high velocity through the combustion chamber. This movement tends to cool hot spots, averages the chamber temperature, reduces detonation and increases power. The shock wave also provides better fuel/air mixing, and this allows the fuel to ignite better and burn faster. A faster burning fuel charge means less timing is required for optimum power output. An example of this--after running my 462 for years with a factory deck height of about .020, we set the deck to 0. There were no other significant changes to the engine (new rings and bearings, but same cam, heads, intake and exhaust systems). The optimum timing setting prior to the change was 34 degrees - that provided the fastest MPH and quickest ET. After the change to 0 deck, the optimum timing using the same Amoco gas changed to only 30 degrees total mechanical. Not only did the lowering the deck RAISE THE CR by several tenths of a point, but by retarding the timing 4 degrees, we were later able to INCREASE the CR even higher due to the optimum lower timing setting. " END Quote<<

[2manyT/A'S]

Originally Posted by Formulajones

To be top dog at the pure stock or the factory stock races I believe the L88 still holds the record. Might be Julie Pennington's car but not sure, there are a handfull of L88's that run so hard to say who has it now. Didn't take people long to realize L88's are an ideal overall package for a dozen reasons. I know once they got below roll bar requirement (11.49) they were told to slow down, lol.

http://www.youtube.com/watch?feature...&v=Z2dW8ToImLs

Thought I heard that the Mahoney/Tieman 68 bird put the L88's on the trailer a few years back???

Can you post some more pics of the gold 70?

What was your best ET?

[Formulajones]

Originally Posted by Formulabruce

Breaking this down a bit....having done this same thing before.... Don't take offense, just trying to justify your results..
1. Seems the CR did get bumped.. which IS logical in this build.
2. Decking the block , Read below a bit from Jim hand on how Both decking and lowering timing because of it, can and does change the CR.
3. Heads. Stock heads are 72 cc, how does one slice off 10K and get 74 cc?
4. Advancing cam to "increase cylinder pressure" >> Fact>> Does Increase the CR....
Im NOT being critical, just stating that what you did do had a huge effect on performance which deviated alot from stock. ( I do like it, I did it, and I didnt like the CR at "dynamic" of 10.5) but I wasnt drag racing it much.
Read some of Jim Hands comments on block decking and its effects...
Quote >>Jim Hand "Deck Height or Deck Clearance:

This most important step consists of measuring the distance from the assembled piston tops to the surface of the block deck (deck clearance), and milling as necessary. The general feeling is that the total quench or squish distance should be about .040". The quench distance is the compressed thickness of the head gasket plus the deck clearance. As most of our Pontiac head gaskets compress to about .042", that means we want about 0 deck clearance. The quench area is the flat part of the piston that would contact a similar part of the head if you had .000 assembled quench height. In a running engine, the .040 quench height decreases to a close collision between the piston and the cylinder head. The shock wave from the near collision drives air at high velocity through the combustion chamber. This movement tends to cool hot spots, averages the chamber temperature, reduces detonation and increases power. The shock wave also provides better fuel/air mixing, and this allows the fuel to ignite better and burn faster. A faster burning fuel charge means less timing is required for optimum power output. An example of this--after running my 462 for years with a factory deck height of about .020, we set the deck to 0. There were no other significant changes to the engine (new rings and bearings, but same cam, heads, intake and exhaust systems). The optimum timing setting prior to the change was 34 degrees - that provided the fastest MPH and quickest ET. After the change to 0 deck, the optimum timing using the same Amoco gas changed to only 30 degrees total mechanical. Not only did the lowering the deck RAISE THE CR by several tenths of a point, but by retarding the timing 4 degrees, we were later able to INCREASE the CR even higher due to the optimum lower timing setting. " END Quote<<

Actually, my compression ratio is lower than "advertised", which is key when looking at the rules. Since these engines never actually had their "advertised" compression ratios in reality, which I explained above. That's what I was trying to get accross. I could have built a 12.25:1 engine if I wanted to, but I chose to keep it pump gas friendly. I could have done all the tricks we are talking about starting with a 12.25:1 engine and been within the rules. I gave up about 8-10% of potential HP with this engine, but,,,I'm not running $8 a gallon gas either.


Zero decking the block, which I do on all my builds, does raise compression, however my main reason is for tighter quench, which as you read Jim Hand touched on. That tight quench promotes swirl and mixture in the chamber which fights detonation. Again detonation is my main concern since this was a pump gas motor.


Not all stock heads will CC at 72. I've been over this before in past posts. They vary give or take a few CC's. 72 is just a number that GM tossed out but I've found with many castings that this number is not set in stone. Mine actually CC'd at 76 after new seats and valve job done, with an extended tip spark plug. Valves were not sunk (that hurts flow ) Then they were milled .010 and CC'd again, came in right at 74CC. This actually worked out in my favor however to keep my compression ratio down a tad, because the overbore and deck bumped it slightly.


When talking compression we have to talk about dynamic and static. Advancing my camshaft didn't increase the static (or advertised) compression ratio. What advancing the cam does is change the dynamic's of the engine, or increasing dynamic compresson (creating more cylinder pressure) by closing the intake valve sooner. It's not exactly the same thing but they do affect how the engine runs. I'm more or less changing the power band of the engine to put it in simple terms. It's just a tuning tool.

[Formulajones]

Originally Posted by 2manyT/A'S

Thought I heard that the Mahoney/Tieman 68 bird put the L88's on the trailer a few years back???

Can you post some more pics of the gold 70?

What was your best ET?

You are probably right, I know Mahoney had some jaws dropping on it's debut, but I'm not up to speed on how close he was to the record, but yeah from what I've seen he was running right there with the L88's. Scott Teimann who restored the car does alot of the driving with it I think.

I can post still pics but they don't stay long as you can see already, I have a setting wrong with either photobucket or my computer that I haven't found yet. Unfortunately when I was running the car often years back, I didn't own a video camera at the time.

ET's varied a couple tenths depending on the weather. Best ET was 13.26, and it would go 104-105 mph.
I'm sure the ram air III cars competing nowadays have picked that up quite a bit since.

[1971455HO]

I have an HO car I've owned for 33 years. I modified it 25 years ago before I even give a damn about the internet and what was out there. I know there is a taboo / stigma attached to cutting the round port heads, but I done it anyway. If you want it too absolutely romp and dont want to deflower your 7F6 heads, you can go this route...

Buy a set of Edelbrock Performer aluminum RA IV heads from Butler. They can machine them to any level of performance you are looking to have. Tell them what you want and they will give you a price. There are several other guys who do head work on here that are just as capable as Butler. So just do your homework and slap an 041 cam in that jessie...you'll love it. You'll also have to fatten up the carb a bit also. If yours is a matching number HO carb, and you don't want to modify it either...contact Cliff Ruggles and tell him what you are building and he can make you a carb that will match your build.

I brought my compression up by replacing my pistons with +0.030" TRW flat tops and angle cutting the heads down to 105CC. The TRW's set higher (taller) in the hole than the stock Pontiac's and give you a virtual "0" deck height without decking the block. My 191 heads were mildly ported, back cut and given a 3 angle valve job. I took it from 8.4 to 9.2. The RA IV cam would work a lot better with CR at 10:5 or even higher. You can do that with no problem with an aluminum head motor and suffer no detonation problems. The RA IV has 87 degrees of overlap built in it, the higher the compression, the better.

One guy said with no engine mods done...you will experience a little sluggishness in the lower rpm range, he's right, you will, for about 1 second when you kick it. If your already in the 2500 rpm range, you'll never know it.

If they would have had the Edelbrocks 25 years ago, I would have been on them with both feet.

All the stuff you asked is purely left to guess work now days. There isn't high octane pump gas. Except for racing fuel (5-6 bucks a gallon) so there is no way to answer you. Don't be afraid to go with a RA IV cam though. Pontiac would have stuffed them in all of their round port motors if it hadn't been for the damn dawning of the Ralph Nader era & the fledgling EPA polution police.

my $0.02

[rexs73gto]

I know this is for the firebirds , but I have to add this. I have a 73 GTO that I wanted to build it as close to an SD car a possible because when I ordered the car I ordered an SD car but of course the order got canceled several times before it was gone for good. I took a left over they had on the lot. After driving it for 29 years with a few mods I built the engine thats in there now. E-heads SRP forged pistons, Cranes Blueprint RAIV cam, Eagle H-beam rods, 1:65 roller tip rockers, RAIV exhaust manifolds, Performer RPM intake, roller gear & chain, Pertronix ign., a modified Q-jet, X-pipe exhaust, M-22 4 spd. 3:73 rear gears. The heads are as they came out of the box, the engine has been completely balanced within 1.5 grams total, block decked just to make sure it was completely level front to back, side to side. I don't know how far the pistons are in the block. OH, this is a 455 + .30. This engine runs really great. It is faster then any SD I've ever got to drive. The car runs 11:50's at an avg. speed around 118-122. I can say nothing but great things about the E-heads when used on the 455 block. With the way I've built this engine I'm sure this is what it would have been if I'd built either an HO or A SD & had reworked the heads back then. So I agree with 1971455HO in his assessment of his engine. If you want to make your HO or SD come alive you can rework the heads to the way they should have been or use a set of the aftermarket heads (Alum.) which will give your car the performance that it should have had from the factory.

[Formulajones]

If you guys want to talk about hotrodding stuff where anything goes, then by all means hands down I recommend aluminum heads and roller cams, and leave the 40 year old dinasour stuff to the resto freaks. But then why stop with a 40 year old ram air IV camshaft. Lets go modern lobes and put a roller in the darn thing and make those heads work for the money they cost. Why spend $2 grand on heads and put a blueprint 40 year old design camshaft in it? That's counter productive.

I built a nice pump gas 455 for my fathers GTO. Edelbrock heads ported by Kauffman, a custom spec hydraulic roller, 10:1 motor, RPM air gap, 950 HP, H beam rods and SRP pistons. Made 602 HP and 640 TQ, yanks the wheels and runs hard. Fun street car for several years.
That motor has since been pulled for a Bischoff built 572 cubic inch pontiac based off Kauffmans block. Same heads (albiet small for this motor now) and a solid roller spec'd by Bischoff. Another pump gas street engine that I'm told will hit the dyno around 800 HP and TQ next month.

[Formulajones]

Here's a shot of the goat running the old motor I put together.

[SD455DJ]

Just to continue this fun debate, at the Pure Stock Drags at Mid-Michigan every fall, the best times for the following:

455 HO is 12.76 @ 109 mph (Mark Weymouth's '71 TA optimized to the rules 9.9:1 compression);

RAIV is 12.31 @ 115 mph (Mark Weymouth's '70 Judge optimized to the rules 12.0:1 compression) Bruno is right there as well;

455 SD is 12.57 @ 112 mph (John Glasgo's '73 Formula optimized to the rules 9.9:1 compression);

RAIII is 12.95 @ 108 mph (Todd Kozak's '69 Judge optimized to the rules 12.25:1
compression);

RAII is 11.54 @ 121 mph (Rick Mahoney's '68 Firebird 400 optimized to the rules 12.25:1 compression) Jim Mino is pretty darn close as well at 11.70's, Rick Watson has some 12.10's

RAI is 12.32 @ 116 mph (Jim Mattison's '67 Firebird 400 optimized to the rules 12.25:1 compression)

These are the best et's for each car and usually happened on Saturday morning warm-ups prior to the match-up racing in the afternoon. It seems that most of the HO's, SD's, RAIV's, and RAII's run together in the 12.50 to 12.70 range quite commonly with the few exceptions above, despite the body/chassis type.

Dennis

[Jack Ferris]

I wonder how one of theses "optimized" engines would ET in a unmodified chassis?

[Formulajones]

It's clear that the ram air IV's despite being down 55 cubes, are making more steam than the HO's and SD's, which was the point of this thread from the beginning. The 455's are unfortunately down compression and camshaft. Given the fact that they all use the rules equally accross the board, the HO and SD handicaps still show here even in this form of racing.
I'm not surprised the ram air III's have picked it up a bit It's right on the heels of the best HO pass. Now there's an eye opener

[Formulajones]

Originally Posted by Jack Ferris

I wonder how one of theses "optimized" engines would ET in a unmodified chassis?

I can tell you the chassis mods are limited with what you can do. Sway bars have to be hooked and functional, no fancy shocks or springs, etc... So you have to get creative such as I described previously. Other things you can do is put water in your spare tire for weight bias, but you didn't hear that from me
Really not much trickery here. But I can say in simple terms that a suspension that works vs another identical car that can't 60 foot is like being down 50 HP. Just an educated guess but probably looking at a 1/2 second in ET difference just in suspension tweaks.