[ponyakr]

Originally Posted by johnta1

Thanks for the links, ponyakr!


I'm surprised they use the same intake/exhaust port cc's for the 455 SD head as the 4X heads in 73/74? (156/142 cc's)

I have no idea where they come up with all the Pontiac specs. Lots of 'em don't jive with the actual specs of the Pontiac engines, as produced.

Don't know why they allow such small chambers, on SOME heads, but don't allow other chambers to be much smaller than stock.

I think I've already mentioned that they allow the SD455 engine in several body styles, besides the Birds. This includes some Lemans, GTO, GP & GA models.

http://www.classracerinfo.com/Engine...px?ENGINE=2080

But, at the current cost of SD455 heads, not many will wanna build an SD455 powered Stock/SS car.

Same with any other round port head engine. Those heads are just worth too much, to race 'em, for most guys. But, for those with deep pockets, what does it matter if heads cost $5k, $10k, or even more. There are lots of old retired guys paying $100k & more for one of the late model FS cars. Lots of younger guys now would not consider a car with a carb, or any car they couldn't tune with a computer. To most younger guys, I suppose the old Musclecars, with a carb, are just antiquated junk, suitable for noting but nostalgia racing.

[Stan Weiss]

Originally Posted by ponyakr

I have no idea where they come up with all the Pontiac specs. Lots of 'em don't jive with the actual specs of the Pontiac engines, as produced.

Don't know why they allow such small chambers, on SOME heads, but don't allow other chambers to be much smaller than stock.

I think I've already mentioned that they allow the SD455 engine in several body styles, besides the Birds. This includes some Lemans, GTO, GP & GA models.

http://www.classracerinfo.com/Engine...px?ENGINE=2080

But, at the current cost of SD455 heads, not many will wanna build an SD455 powered Stock/SS car.

Same with any other round port head engine. Those heads are just worth too much, to race 'em, for most guys. But, for those with deep pockets, what does it matter if heads cost $5k, $10k, or even more. There are lots of old retired guys paying $100k & more for one of the late model FS cars. Lots of younger guys now would not consider a car with a carb, or any car they couldn't tune with a computer. To most younger guys, I suppose the old Musclecars, with a carb, are just antiquated junk, suitable for noting but nostalgia racing.

I am not sure what you mean by this. It does not matter what a head measures when you pull it off of a untouched stock engine. The specs for what the engine specs should be to the best of my knowledge were given to the NHRA by Pontiac.

Stan

PS - It is a long time ago. I still seem to remember back in the day that some manufactures played games and gave specs to NHRA that help the racers of that brand.

[ponyakr]

OK, here's an example. For the '70 455, which had #64 heads. LOOKS like NHRA allows you to cut 'em down from 87cc to 75cc. That's quite a cut, IMO.

http://www.classracerinfo.com/Engine...0&MAKE=Pontiac

BUT, for the 1977 350 , which came with 6x-4 heads, they only allow a cut down to 91.11cc. That is a very small cut.

http://www.classracerinfo.com/Engine...3&MAKE=Pontiac

It shows that the 6x-8 heads, on a 180hp 400 can be cut down to 89.06cc. Don't make sense that the 400 chambers can be smaller than the the 350 chambers. Wasn't that way from the factory, unless it was a W72 400, which was suppose to have the same heads as the 350.

http://www.classracerinfo.com/Engine...4&MAKE=Pontiac

Actually appears that they allow the same size chambers on the W72 engines as on the lower power 400 engines.

http://www.classracerinfo.com/Engine...7&MAKE=Pontiac

Maybe that's the reason so many have run that '77 180hp 400, thru the years.

[Stan Weiss]

What an I missing? Why does it matter what / how much you can cut the heads?

You still have an adv CR and a listed max CR for the specs.

455 10.25:1 12.44:1
350 8.35:1 8.71:1

Stan

Let me add - Or we can look at this differently. Why did some heads came from the Pontiac closer to what their stated specs were than other heads?

[ponyakr]

Let me use this as an example.

The 300hp engine, in a '68 bird has always been a very popular combo.

NHRA will allow you to cut the heads down to 65cc. It has been posted here, several times that SOME of the legal #62 heads came from the factory @ around 75cc, or slightly more. So, to me a cut of 10cc is a pretty healthy cut, & should increase the CR of that engine, over using 75cc heads.

I don't know how to explain it any better than that. So, that's all I'm gonna say about chamber size. If you build a class racer engine, you can't run smaller chambers than the min listed by NHRA.

The whole deal here is to have some of you guys who know how, use the given NHRA engine spec rules, & figure out how much power can be made with the particular engines mentioned, WITHOUT max allowed head porting. Again, it has been posted that it could cost up to $10k, or more, to have a set of SS heads built to the max of the rules.

I wanna know which of the engines mentioned might be the most competitive, under NHRA SS rules, WITHOUT building the hears to the max. It seems that a car needs to be able to run at least a full sec under it's index, in order to win most of it's same-class, heads-up runs.

I'm NOT trying to figure out how to run a sec under the index. I'm trying to figure out which Pontiac engines might be built, which will just barely run the index, or just slightly under.

JUST ASSUMING that a barely-under-the-index engine can be built, WITHOUT fully porting the heads.

This is assuming that the car is properly set up with the correct converter, trans brake, rear gears, suspension & tires.

I've read here where some of you guys estimated the power lots of street combinations will make, using different parts. Just assumed that the same calculations could be made using the SS engine rules.

Car weights & class indexes are all listed on the classracerinfo.com site.

As a further aid, there are lots of online calculators, that are supposed to tell you how much hp is needed to run a certain ET, with a certain weight. Don't know how accurate they are.

BUT, if ALL the calculators agree that you need 500hp to run the index, with a certain weight car, & you can figure that the most power you can possibly make with a certain engine, without extensive high dollar head work, is only 400hp. Then obviously, that might not be a good choice for a SS engine.

Just asking for simple calculations of what power & torque these engines mentioned can make, without high dollar head work.

Sorry, but that's the best I can explain what I'd trying to determine.

[Stan Weiss]

So just how much are you willing to spend on the trans? Light weight parts, different gear ratios?

Stan

[ponyakr]

I want to establish this once & for all.

I am NOT building a Super Stocker, or a Stocker, and will not, unless I win a BIG lottery ! OK ???

As for the questions ask.

I realize that there are small gains to be made by using the latest trick TH200 trans & the very best high dollar 8" converter.

But, as I THOUGHT I made clear, I'm just speculating as to what it would take to build a SS Pontiac ENGINE that will run just barely quick euff to run it's index & just a hair under, since you can't dial any slower than the index for your car.

So, for the car itself, let's just assume it will have the correct rear gear & stall speed converter for the car & engine/cam chosen, and will have a nice TH350 with a 2.75 1st gear ratio.

WHAT I'M ASKING IS FOR SOME OF YOU GUYS WHO DO SUCH THINGS, TO ESTIMATE HOW MUCH POWER CAN BE MADE WITH EACH OF THE ENGINES MENTIONED, WITHOUT PAYING THE BIG BUCKS TO HAVE THE HEADS TREATED TO THE MAX ALLOWED PORTING, UNDER THE NHRA SUPER STOCK RULES.

I thought some of you guys had all sorts of computer programs, with which you can calculate the power most any engine will make. Or will those only work for street engines ?

Like, for a '77 350 Pontiac engine, under SS rules, without max head work, is the engine capable of 400hp, 450hp, 475hp, 500hp ?

Same question for a '70 455 engine. Plus, for the 455's, the torque would also come into play. The big torque could be used, rather than quite so much rear gear, stall, & high RPM.

The rods will be the legal 760 gram Eagle H-beams. The pistons can be Ross, Race Tec, CP. ect. BUT, Adam Strang had posted that he ran TRW pistons in his Stocker for years. I think he said he even set a nat record with those pistons. But, the race pistons will be lighter & have deep reliefs, for use with a big cam.

Speakin of cams, some of the Pontiac Stockers that are running mid to low 10's, are running flat tappet cams, with .425 & less lift. So, for SS, I suppose it MIGHT be possible to run the index with the correct solid flat tappet cam.

With the head limitations as mentioned, I don't know exactly how much power/ET difference we're talkin about, between a solid flat tappet & a roller cam. Maybe some of you guys can calculate that for us, also. As far as I know, there are no lift or duration limits, for SS.

[ponyakr]

After thinkin about it some more, I suppose quite a bit of power could be made with a big HFT cam & Rhoads V-Max lifters.

For this racing application, you can forget about any low rpm street manners. Only consideration is getting the duration right to make max power in exactly the right rpm range, for the engine in question.

I looked up some big shelf HFT cams. None had 250° @ .050 duration on the intake lobe. But, some had mid to high 240's.

Just assuming that a SS 455 could make 500hp with one of these cams. I think I've seen several dyno results showing 500 + hp for STREET 455's, using slightly smaller cams. And those engines were supposedly very streetable.

Here are a few of the larger HFT shelf cams.

https://www.lunatipower.com/voodoo-h...8-284-292.html

https://www.summitracing.com/parts/crn-284571/

https://www.summitracing.com/parts/crn-280451/

https://www.jegs.com/i/Crane-Cams/271/280601/10002/-1

https://www.summitracing.com/parts/c...caAt4AEALw_wcB

http://www.pbm-erson.com/Catalog/Ers...t_E/ERSE310444

I suppose to get more duration, with a HFT cam, you'd have to go to a custom. Bullet has you covered, with just about anything you could want. They supply cams for a lot of the 10 sec Stockers.

http://www.bulletcams.com/Masters/Hlobes.htm

So, for you Pontiac cam gurus, aprox what would be the power potential difference, between the best HFT cam, the best SFT cam, & the best roller cam, for a 350, a 400, and a 455 Pontiac SS engine ? Is there any way to estimate the difference, without doing dyno testing ?

SD posts that 455+ iron head engines, made a bit over 500hp, on pump gas, using their smaller HR cams. But, the heads they used had their CNC porting done. I'm assuming that by using more cam, & compression, plus race gas, a 455 engine should easily be able to make that 500hp or more, without fully ported heads. I don't know if SD has a SS legal porting job available, or not. I assume he spends all his time workin on street stuff.

So, have any of you guys done a basic SS mild legal porting job to any Pontiac iron heads ?

I don't have a rule book & don't know exactly what is allowed. So, I don't know how much flow can be achieved, with a basic legal port & valve job.

The heads seem to be the choke point. So, does anybody here have more insight into what would be the min required, legal head work, to build a set of heads that would flow enuff to make the power required to run the index, in a properly set-up Pontiac, with a decent engine/body combo ?

[ponyakr]

According to this Wallace Calculator, it would take aprox 520hp to run 11 flat in a 3500lb car.

http://wallaceracing.com/et-hp-mph.php

If you reduced the weight to 3300lbs, only 490hp would be required.

To run 10.80 @ 3300lbs would require 518hp.

Don't know what car equipment is being assumed, in the calculation. I assume that a light converter & trans, plus a trans brake might mean that less hp would be required to run the same ET.

This TCI calculator shows that a 3300lb car with 500hp will run 10.85. So, I suppose this calculator is close to the Wallace calculator.

https://www.tciauto.com/racing-calculators

Does anybody know of a more accurate drag racing calculator ?

Here's the next one I pulled up. It's not even close. My 455 Ventura bracket car was a good bit quicker on the 60' & 1/8 mile times than this calculator shows, for a 500hp 3300lbs car. My car weighed more & had less hp. Also only had a 10" converter, & I was foot braking, leaving at 2000rpm.

https://robrobinette.com/et.htm

Here's one that's even more ridiculous. It says I'll need 637hp to run 11.00 with a 3300lb car. WOW !

https://timmcamis.com/media/calculators/hp.html

I can only go by cars I had. The last car TJ drove was a '67 Bracket bird. It had roll bars, so I assume it weighed at least 3300lbs with TJ in it. Best ET was 11.82. It was just a TRW 455, with unported big valve D-port heads. Had a TH400, with a stock converter & 4.11 gears. I'd guess it had a little over 400hp/500 torque. Let's see what the calculators say.

TCI says it only takes 386hp to run 11.82 @ 3300lbs. But, considering the car didn't have a stall converter, that's probably pretty accurate. Since I had 400hp or maybe a little over, that made up for the stock converter. Wallace calc says 395hp. So, I reckin both those calculators are pretty close, or at least will get you in the ball park.

[ponyakr]

I suppose that for a budget GT class car you'd wanna go with one of the lower classes, which would be I thru Q. The GT/IA index is 10.65. The GT/QA index is 11.75.

http://www.classracerinfo.com/NHRA_Classes.aspx

An example of a Pontiac GT/IA combo might be a '70 455 in a '68 Bird. It's a 10lb/hp class, so 10 x 335hp = 3350lb car. It would have to run at least a 10.65, in the worst conditions it would face in competition.

http://www.classracerinfo.com/Engine...0&MAKE=Pontiac

On the other end, a GT/QA is a 14lb/hp class. So, an example might be a 2nd gen Bird or some A-body that could legally weigh about 3500 lbs, with a '77 350 engine. 14 x 250hp = 3500lb car. This car would have to run at least an 11.75, in the worst conditions, to always run it's index.

However, for this particular engine, it would be best to run it in a '77 Bird, since it would only have a 246hp factor.

http://www.classracerinfo.com/Engine...3&MAKE=Pontiac

A '73-'74 D-port 455 could run GT/JA @ 3255lbs in a 1st gen Bird. Index is a 10.80. So, the car would be 100lbs lighter than the GT/IA I mentioned above. And the index is .15 slower. So, which car would have the best chance of running it's index or quicker ? Hey, it ain't no life & death problem. Just somethin to think about or calculate, during a cold rainy Winter day. It rained all day & all night here. Fraid some of those folks along the rivers in Northeast LA & most of MS, might be in for some severe flooding.

http://www.classracerinfo.com/Engine...9&MAKE=Pontiac

I have to think that the '69 350hp GTO engine might be one of the most competitive Pontiac SS engines, at a 310hp factor, in GT. Would be better in a '69 GTO, @ 306hp. But not many gonna put a '69 GTO on the track now, I suppose. At least not one that's clean enuff to pass NHRA Tech in SS.

http://www.classracerinfo.com/Engine...4&MAKE=Pontiac

[400 Lemans]

Couple of large hyd flat tappet cams.http://schneidercams.com/160Hponhydraulic.aspx

[400 Lemans]

http://iskycams.com/shop/index.php?m...oducts_id=1023

[ponyakr]

Did a little checkin on what some Stockers have run using these some of these engines.

(1) 1st one I checked was the 1970 GTO 455. The only one I know of which has run in recent years belongs to Todd Kuhn. Saw some times in the 11.20's. That was running F/SA, which is a 10.5 lb/per hp class.

The Stock hp factor is 340hp. So, 10.5 x 340 = 3570lbs. I assume that you must also add 170lbs for driver weight. If so, that means the car has to weigh at least 3740lb.

It is often said that a rule of thumb is that every 100lbs of weight equals a tenth on the track. If that is applied to this engine, it should run aprox .3 quicker, in a 3350lb car. That would put the car into the 10.90's. And that's with an iron intake & .425 lift flat tappet cam.

So, how much quicker would the car be with the correct larger cam & alum intake ?

I don't have a clue how much head work Todd's engine has had. Would love to know. Also don't know if he's running all out, or leavin some on the table.

For most of those Pontiacs currently capable of running a sec or more below their index, we pretty much know they have the max high dollar heads. For any who can & don't have high dollar heads, I'd sure like to know exactly what has been done to the heads. I suppose that will remain a secret, for most class racers.

[ponyakr]

I think Brent Flynn ran maybe 11.30's or 40's, in his low budget '68 Bird Stocker. He didn't have money for the high dollar heads.

NHRA gave his '68 330hp engine a hit, up to 338hp, at that time. He was running E/SA, which is a 10lb/hp class. So, his car had to weigh 3380lbs, plus 170lbs for driver, I assume, which would make the total weight 3550.

Basically the same engine, would be the '69 GTO engine I mentioned, at 310hp, in GT.

That engine could run in the 11lb/hp GT/KA class, at 3410 lbs, which has a 10.90 index. So, basically Brent's engine would have to go nearly a half sec quicker, to run the GT index.

That's where some of you expert engine builders come in. Could Brent's car run a half sec quicker by only changing the cam & intake, along with adding a tranny brake & the correct converter ? Or would more head work and/or a lighter trans be needed ?

Also, Brent's engine had the heavier Stock legal pistons, which are not required in SS.

Again, these are just ideas & questions about how to possiblly come up with one or more Pontiac combos that could be built, WITHOUT buying the HIGH dollar max head work.

If anybody knows of any dyno info that might shed any light on this situation, please post that info or links to it.

May have been some posted on this site. But I wouldn't even know how to do a search that might turn up something helpful. I assume that most dyno info involves fully ported heads, alum heads, round port heads, or heads that have some porting that would not be legal in SS. But hey, I could be wrong.

[ponyakr]

Originally Posted by 400 Lemans

http://iskycams.com/shop/index.php?m...oducts_id=1023

Yeah, I don't know how those single pattern cams would work, with unported D-port heads. It has been posted that John Schloe ran a big single pattern in his RA4 engine. But, that had round port heads.

BUT, I think most cam companies will take any of the lobe profiles they have, & grind a dual patter cam, with whatever LSA you want.

So, I suppose you could have one ground with the 2 biggest lobes offered, and maybe a 108 LSA ? Don't know what cam company would grind one like this for the best price. Assuming most will charge at least $200. But, I don't know that.

So, for some here who have recently had a custom HFT cam ground, what was your total shipped cost ?

Howards shows some HFT lobes with from 253° @ .050, to 263° @ .050. Should be able to come up with a cam from those lobes that will make some power. They also show the low lift "square lobe" cams like the Stockers run. Didn't know Howards offered those Stocker grinds.

https://www.howardscams.com/sites/de...01-20-2014.pdf

Also found some CC lobes they call "Race Hydraulics", which go for 260°@ .050, to 276°@ .050. They're on page 13.

https://www.compcams.com/lobe-catalog

[400 Lemans]

https://www.facebook.com/brent.flynn...user_video_tab Sounds wicked. 256/262 @ .50 with .425 lift. Love that car.

[Stan Weiss]

Originally Posted by ponyakr

According to this Wallace Calculator, it would take aprox 520hp to run 11 flat in a 3500lb car.

http://wallaceracing.com/et-hp-mph.php

If you reduced the weight to 3300lbs, only 490hp would be required.

To run 10.80 @ 3300lbs would require 518hp.

Don't know what car equipment is being assumed, in the calculation. I assume that a light converter & trans, plus a trans brake might mean that less hp would be required to run the same ET.

This TCI calculator shows that a 3300lb car with 500hp will run 10.85. So, I suppose this calculator is close to the Wallace calculator.

https://www.tciauto.com/racing-calculators

Does anybody know of a more accurate drag racing calculator ?

Here's the next one I pulled up. It's not even close. My 455 Ventura bracket car was a good bit quicker on the 60' & 1/8 mile times than this calculator shows, for a 500hp 3300lbs car. My car weighed more & had less hp. Also only had a 10" converter, & I was foot braking, leaving at 2000rpm.

https://robrobinette.com/et.htm

Here's one that's even more ridiculous. It says I'll need 637hp to run 11.00 with a 3300lb car. WOW !

https://timmcamis.com/media/calculators/hp.html

I can only go by cars I had. The last car TJ drove was a '67 Bracket bird. It had roll bars, so I assume it weighed at least 3300lbs with TJ in it. Best ET was 11.82. It was just a TRW 455, with unported big valve D-port heads. Had a TH400, with a stock converter & 4.11 gears. I'd guess it had a little over 400hp/500 torque. Let's see what the calculators say.

TCI says it only takes 386hp to run 11.82 @ 3300lbs. But, considering the car didn't have a stall converter, that's probably pretty accurate. Since I had 400hp or maybe a little over, that made up for the stock converter. Wallace calc says 395hp. So, I reckin both those calculators are pretty close, or at least will get you in the ball park.

You need a simulation that looks at the whole time slip. Many of these cars run very good / excellent 60 foot time and lower MPH than one would think from their et. WAG what a time slip would look 455-460 HP and 3720 lbs

60 Foot ET = 1.4407
330 Foot ET = 4.3920
1/8 Mile ET = 6.9749
1/8 Mile MPH = 94.7443
1000 Foot ET = 9.2466
1/4 Mile ET = 11.2159
1/4 Mile MPH = 113.7752

Stan

[ponyakr]

Originally Posted by 400 Lemans

https://www.facebook.com/brent.flynn...user_video_tab Sounds wicked. 256/262 @ .50 with .425 lift. Love that car.

Yeah, those low lift, square nose cams sound good. Probably sound better than most street HR cams. But, they don't have to worry about street manners, at all. Just trying make max power in the correct rpm range for the engine/combination involved.

Just think about how the cams sound, in the Stocker engines that turn 8000 rpm.

The unlimited cam duration & spring pressure, is what many say made the Stockers so much quicker, and what made 'em cost so much. Many say that in some ways, those rules ruined Stock Eliminator. As long as there was limited spring pressure, checked by techs, on a regular basis, not many cars could turn 8000 rpm. Nowadays, I fingure there are LOTS of Stockers going well past 8000. Probably some going past 9000 rpm. Don't have a clue what the little 302 Chevy & 340 Mopar engines are turning. But, as quick as they're running, they gotta be windin 'em up pretty tight.

If Randi Lyn is turing 8000 +, with a 3.75+ stroke, then you know the short stroke engines are screamin. And the 302's have a max stroke of 3.02, & they can run .485 lift. Hey some of those engines may be turning 10,000 rpm or more. Anybody know ?

http://www.classracerinfo.com/Engine...MAKE=Chevrolet

[Stan Weiss]

I don't use this software very much. I let the software pick the cam specs for best HP.

Stan

[ponyakr]

Got a pdf copy of the 2014 NHRA rule book.

Here's what it says about driver weight.

"...Class is determined without
driver weight. Once classification weight is calculated, 170 pounds
will be added for driver to arrive at minimum weight..."

Here's the head rule.

"...CYLINDER HEADS
Must be correct casting number for year and horsepower
claimed, per NHRA Technical Bulletins or NHRA-accepted.
Cylinder-head casting must also be on NHRA runner volume list
as published on NHRARacer.com. Porting, polishing, welding,
epoxying, and acid-porting permitted. Grinding and polishing in
combustion chamber permitted. Welding and/or applying epoxy
in combustion chamber prohibited. Spark-plug hole must
maintain the stock location, size, and angle as machined by the
OEM; spark-plug adapters prohibited.Valve-guide centerlines
must maintain the stock lateral and front-to-back location as
machined by the OEM.Valves must maintain stock angle; valvestem angle must remain stock, +/- 1 degree. Cylinder head must
be able to hold combustion chamber, intake and exhaust runner
volumes per NHRA Specifications. Any aftermarket steel valve
permitted; must maintain stock head and stem size; titanium
valves prohibited. (OEM sodium-filled valve may be replaced with
titanium, provided weight is equal to or greater than original.)
Valve diameter permitted to be +.005-inch or -.015-inch from
published NHRA Technical Bulletins. External modifications
prohibited, intake side of head may not be cut into any part of
valve-cover bolt holes (except for SS/AH).Valve-cover bolt holes
must remain unaltered and in their original location. Welding or
epoxying permitted on external portion of runners for repair only,
maximum 2 runners per head. Heat riser passages may be
blocked off from intake-manifold side of cylinder head or in
exhaust port. The following are permitted: polylocks, jam nuts,
screw-in or pinned studs. Any valve job accepted. Exhaust plate
permitted between header and cylinder head, maximum 1/2-inch;
may not protrude into exhaust port. Cylinder head may have all
seats replaced..."