New Obsession...V2
 

Well, since my original thread went missing when PY was getting hacked this past summer, I decided to start a new version (V2.0) of it, but without all the history. Long story short, I bought a nice'70 Tempest 2-dr post coupe last December from Florida and immediately set out to tearing the 462/TH400 and interior to 'fix' a few things. I always wanted to build a '70 Tempest post coupe Pure Stocker with the XV code 400 4-bbl with the small valve 10.0 to 1 #16 heads just to see what it could do. The TH400 is freshly rebuilt to HD specs with a Continental 13" convertor and a 3.42 geared 12-bolt rear end. Not the best for the 1/4 mile, but a good compromise gear since I'm going to drive it more on the street.

The new 400 motor is based on a F240 YS block, D160/E200 heads, and a B190 intake with a 7040264 Q-jet and log exhaust manifolds. The heads were rebuilt with new Ferrea 6000/6001 valves, Comp 990 springs, 10 deg retainers and std. valve job (no back cutting the valve head, etc.) and cc'd at 78.0 cc's average (+/- 0.5 cc) after a clean-up cut (80 cc original factory). The block was bored .030" over and the crank cut .010/.010, new RPM 4340 I-beam forged connecting rods and forged Icon 2618 pistons with 2-1/16", 1-3/16" rings (full floating). The mains were machined for .0024" clearance and the rods .0021". The block will be assembled in the near future and we're thinking the actual static compression ratio will be close to 9.75 to 1 with .040" quench. A Summit 2800 cam (204/214/112 at .422"/.444") & lifter kit is planned to replace the 066 factory piece. The exhaust will include the Pypes 2.5" mandrel headpipes for log manifolds (no X-pipe...gasp!) and Dynomax Ultraflows (18" case) and 2.5" tailpipes. We will dyno the motor late October hopefully and should see 350 hp and 450 lbft torque.

More to come! Dennis

The Tempest....

Dennis

Love the pics! Sleeper right there!

Thanks Indymanjoe! The previous owner ran a couple of 11.90's at 113/114 mph in the summer Florida heat on G70-14 Wide Ovals.

Dennis

Thanks for re-posting V2.

Your car looks awesome! The photo is saved in my "I wish mine looked like this" folder...

Hope the engine goes the way you want it. Very cool to see a Tempest with this kind of vision for it.

Thanks Shiny! I believe you helped me with the front bench seat saga with the seat belt passage to the floor connection. I'm glad that was solved and I can focus my attention on the motor and getting it running and driving again (next spring most likely - unfortunately).

Dennis

Very nice car. Is that Palissade Green? Looks like Springfield Green from '72. One of my car was born this color. Not a big fan, but it looks awesome on your car with the steel wheels!

Think I was following the 1st thread, subscribing regardless, like the project!


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MescaBug...Yes, it is a slightly brighter version of Palisade Green (the original color). Believe it, or not, the factory listed dark green (Pepper green) for the steel wheel color when no full wheel discs were ordered. I think matching the body color looks best, but I may paint another set Pepper just for yucks.

Dennis

HWYSTR455...I recall that you took a picture of the dealership the car was ordered/sold at in Ashland, VA (Cardinal Pontiac-Buick on Rt-1?).

Dennis

No kiddin. I wonder why they didnt paint match the car/wheels. Pepper green is a lot darker than Palissade... Black would've been a better choice IMO, instead of different shades of green... :confused::confused:

Can you imagine pepper green wheels on a Verdoro green car? They called Verdoro a medium color and pepper dark.

Dennis

Dennis;

I am curious, since you're doing a "stock" rebuild, why the camshaft that would make it illegal to run in the PSMCD?

I too was following the old thread - and didn't realize it went away after hte last time this site was down... so re-subscribed!

Jonny, We found it very hard to police cams at the race, so we use the 16 in. vacuum at 1200 rpm the rule to adhere to. We also found that the cams that produce good vacuum, even very tame ones can go quick. I have the 2800 on the shelf and want to use it. The Desktop dyno said it made a whopping 5 hp and ftlb more than the 066. The 066 is a good cam at 200/211...so very close.

Dennis

/\ fair enough.

Thanks for humoring my (quite probably annoying) query.

I'm pretty sure I mentioned it in the "lost" thread", but it bears repeating, I really prefer the 70-tempest front bumper treatment over the 71/72 treatment.

No, not at all. Always glad to help Jonny.

Dennis

Our original PSMCDR cam rule of 1%/2% deviation on .050 duration/lobe lift isn't practical to enforce or police at the race when so much is going on. It is easier to attach a good vacuum gauge to the motors and see what they do at 1200 rpm in neutral. Exceptionally quick cars do get the once-over really good with a P&G (measures cubes), Whistler (measures compression ratio), and durometer check of the tires. We will yank a valve cover to see if roller rockers are present and also check torque convertor stall if its an automatic.

It's interesting that guys have found out that high(er) stall convertors hinder good et's on street tires and repro wide ovals. It's too easy to blow the tires off and be consistent, so tight (stock) convertors are the needed to kill too much low end torque.

Dennis

That car looks awesome, Dennis! The plain wheel with those tires is a fantastic combo. Reminds me of the T-37 Tom Miller and his dad finished a number of years ago. He ended up selling it to someone on this board (wish it was me!).

Vince

Dennis, your '70 looks good. Personally believe the pepper green steel wheels will give it a little contrast & really give a good look From the assembly plants, seldom did '70-72 Pontiac A-body's with poverty caps have same color wheels as body color, too many times the matching color steel wheels look contrived. Dave Hall has a 72 LeMans Coupe on eBay right now. Monarch Yellow with same color wheels & poverty caps...just does not look right.

Thanks Roger & Vince!

Here is the short block assembled and the pistons are all around .001" in the hole, which means we can use the Felpro 1016 head gasket with .039" crush to make our .040" quench goal and keep the compression around 9.75 to 1 to run on pump premium (93 octane in our area).

Dennis

The static compression worked out to 9.94 to 1 exactly and cam was degreed in to be -2 (best Desktop Dyno numbers with the 2800...actually with the 2801 & 2802 cams too for yucks). The dipstick tubes and windage tray are installed, so now the heads are next. The Desktop Dyno is predicting 359 hp at 5000 rpm and 432 lbft at 3500 rpm. It'll probably be closer to 350 hp and 440 lbft., but we'll soon see.

Hopefully break-in will be in a couple weeks ,then to the dyno to see what a small valve 400 will do in pure stock form with just below advertised compression (10.0 to 1).

Dennis

Getting closer...heads on, quench at .040" and the pushrods, rocker arms & pivots, guide plates, oil pump & driveshaft, fuel pump eccentric, and a few other pieces and she's ready to break-in of the test stand.

Dennis

The day of reckoning is finally here! Any guesses as to what this 400 (406) will make on the dyno?

This motor is built for the pure stock drags and is based on the small valve 400 4-bbl available on both A & B bodies (non-GTO) that has 10.0 to 1 advertised compression, rated at 330 hp and 430 lbft torque. The stock factory cam is the 066 cam rated at 273/282 (200/210 @ .050” lift) and .413” lift.

The XV 400 motor build is finished, broken in on the test stand, and goes to the dyno tomorrow. To recap, the block is a late ’70 400 block (F240) that is .030 over (406 cu. in.) with Icon forged pistons (1/16” - 1/16” – 3/16” rings), RPM 4340 I-beam forged rods, stock N-crank, balanced with careful rebuild (not blueprinted). The pistons are off-the-self 400 + .030 pistons with the 1.720” pin (compression) height, 4.5 cc valve reliefs and .0015” in the hole. The head gaskets are Flepro 1016’s with .039” crush thickness for a quench of .041”.

The stock small valve # 16 heads (date castings D160 & E200) measured in at 78 cc’s after a slight clean-up cut (80 cc’s factory) with a calculated static compression ratio at 9.94 to 1. The stock pressed-in rocker studs were pinned (like in the good ol’ days) with stock 1.5 stamped rocker arms and factory pushrods. The valve springs are basic CC-990 with 120 lbs seat and 240 lbs @ .400” open pressure (5600 rpm max. shift points). The valves are 1-pc SS 1.96”/1.66” Ferrea’s with 45 degree faces/seats (no back-cutting of the valve heads). The heads weren’t flow benched, but other small valve heads flowed around 190-195 cfm intake/150-155 cfm exhaust stock.

The Q-jet carb we used on the dyno is a 7041264 (’71 400 auto application with 73/43 primaries and CC secondary rods to start out with) on an untouched ’70 cast iron intake manifold. The distributor is from a ’69 400 manual trans application with a Crane XRi electronic replacement ignition. The exhaust manifolds are the std. A-body log style with 2-1/8” openings flowing into Pypes mandrel bent 2.5” head pipes 4’ long.

The cam originally selected was going to be the Summit 2800, but we decided to go with the 2801 instead because of the higher compression to bleed off a bit more cylinder pressure since this is a street driven car 95% of the time. As discussed earlier, the Pure Stock Drags now base cam limitations on the engines ability to maintain 16 in. vacuum at 1200 rpm in neutral. The 2801 does that easily and (actually closer to 20 in.) and is very mild with minimal lope. It is essentially a high lift version of the factory 068 cam (214/224/112 @ .444”/.466” lift). Interestingly, the Desk-Top Dyno predicted 341 hp/445 lbft for the 2800 and 359 hp/429 lbft for the 2801, so very little difference and a trade-off of torque for horsepower. The 2801 was installed straight up as the DTD predicted the highest hp/tq and averages at -2 degrees with the 2801 valve timing specs anticipating timing chain stretch.

The ’70 small valve YH code 455 (462) I dyno’d a few years ago with the same compression and exhaust logs made 391 hp/512 lbft torque with the 2802 cam.

What you’re your predictions?

Dennis

I'll take a shot, just for fun:

310hp/365tq

Guessing it will be dependent of the type of dyno too, but went a little soft on purpose. It will probably pick up after say 10k miles or so too, after it loosens up some and along with fine tuning.


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Yeah, that's right, but actually, think I found them on the 'net. I remember saying I go down there several times a year to visit family, but can't remember if I actually took pics or not.

I will poke around again and see if I can find a pic or two from back in the day.


Note: I'm not very good at guessing output.


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Loving this build.

Dynoing in 30 minutes!
 

Today is Dyno Day!

Any other guesses what the motor is going to make?

Hopefully I have good news this afternoon to report.

Dennis

I'm going for 330HP/410TQ.

Let us know!

Dyno Results
 

We made 14 pulls (3000 to 5500 rpm) in 2 hours and were pleasantly surprised with the results:

Corrected (Uncorrected): 383.9 hp (357.5 hp) @ 5300 rpm and 454.1 lbft (425.4 lbft) @ 3600 rpm (pull #11 with the highest torque). Pull #12 (no changes – back up for pull #11) netted the highest corrected hp at 384.7 with max torque a tad lower at 452.5 lbft. The highest average power was pull #12 at 343.8 hp and 423.7 lbft torque through the 2500 rpm range. We were surprised how the power hung on to 5500 rpm (the TH400 trans governor is set up to shift at 5600 rpm automatically).

The timing was set and left at 36 degrees for all 14 pulls. The exhaust system off the manifolds was Pypes 2.5” mandrel headpipes tied into another 8’ of 2.5” flex and straight pipe (12’ total length). The 7041264 Q-jet started with 73 jets/43 rods on the primary side and CC .030” M tip secondary rods on a ‘K’ hanger. The secondary rods were changed 4 times more getting leaner with every change…to CE - .0410” M tip; then DR - .0570” M tip; then CL - .0667” M tip; and finally CG - .0774” M tip, which were the leanest we had and still a tad rich. We then swapped in a ‘T’ hanger which leaned it out enough for decent BSFC’s (0.467 avg.).

The max corrected hp/tq with the 2.5” exhaust pipes was 380.7 hp/451.1 lbft. The most power (pulls #11 & #12) were made with the Pypes headpipes dumping into big 6” diameter straight pipe and swapping back in the ‘K’ hanger on the carb. It didn’t like the baseplate on the carb and lost a 4-5 hp and tq.

Oh, we used a 50/50 blend of 93 octane and 110 octane gas just to make sure we didn’t have any detonation as the knock sensor wasn't working. The motor ran beautifully without a hiccup or any blow-by. The rings are definitely seated now.

Dennis

Here are Pulls 11 & 12 dyno sheets (corrected).

Dennis

wow!!!
and this isn't even a "high performance" 400!?

I wonder how bad you might smash the results printed in the older Musclecar Review magazine that did 'pure stock' type pulls on a RAIII & RAIV!?

Wow. Impressive results. I expected a little less from the 2801 cam. I’m a big fan of log manifolds for this type of built. Easy to install and they look good tucked under the heads. And they dont hang low as most headers do.

Any porting done to the heads?

Great work! Keep up posted.

Thanks Jonny and MescaBug. No, the heads are bone stock but with new Ferrea stainless steel valves and Comp Cam springs, retainers and locks. They even have the 45 degree seats.

My stock 11 to 1 RAIV dyno'd at 455 hp at 495 lbft torque, so am assuming a RAIII with the same compression as the IV would be 420 hp and 475 lbft range.

Dennis

I think the uncorrected hp/tq seems more realistic to me than the corrected power numbers. The dyno assigned a correction factor of 1.067 (6.7%) for the pulls, which seems optimistic. I was flabbergasted by the corrected numbers as the pulls were made. Even the best uncorrected pull (#12) yielded 358.2 hp @ 5200 rpm and 423.9 lbft torque @ 3700 rpm was very close to the usually conservative Desktop Dyno’s (DTD) 361 hp/431 lbft prediction.

The dyno weather station reported 68*F (using inside air for the session), 47.1% relative humidity, 28.86 Hg barometric pressure (steady), and 2083’ air density altitude (866’ actual above sea level). Many of the correction factors (DIN, SAE J-607, SAE J-1394, STD, etc.) use different measurements for their correction factors and when you plug in the weather data for the time of the dyno session. When plugging in the weather data into the Dyno Corrections Factors calculator from the VSeriesForums, I got correction factors from 1.019 to 1.053 adjusting the corrected horsepower for the best pull (# 12 @ 358.2 hp/423.9 lbft) from 364.90 hp/431.82 lbft to 377.05 hp/446.21 lbft. Plugging in the DTD numbers, they corrected from 367.75 hp/439.06 lbft to 380.00 hp/453.68 lbft. (BTW, I used the same factors to calculate the torque).

Using these correction factors for the DTD engine with the 2800 Summit cam of 341 hp/445 lbft, they adjusted from 347.37 hp/453.31 lbft to 358.94 hp/468.41 lbft…if the DTD numbers are to be believed. The torque seems high at 445 lbft to me, but who really knows for sure.

Anybody care to see what they get on any other calculators out there on the web?

Regardless, I’m impressed with the uncorrected numbers this motor build made and the drag strip performance (next year unfortunately) will truely tell us what the engine makes.

Dennis

Regardless, those are great numbers, congrats!

I have the older version of DD, and would usually just deduct 10% of it's numbers for personal info, would give results I thought would be closer, but who knows. You change intakes in that program and it has drastic jumps, so have always been skeptical.

Funny how across different dynos the numbers can be all over the place, so in general, it's only a reference is what I tell myself. Still tho, anyway you look at it, those are still good numbers.

I was trying to dig up that pic again, looked for a while, here & there, over the course of a day, no luck. It might be on my other computer, will look again when I get a chance.


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Thanks Hwystr455! You don't have to worry about finding that picture of the dealership, or what resides in its place now.

I think these small valve motors are sleepers and make more power than anyone thought. I'd love to find a real Tempest or Lemans equipped with one from the factory with minimal options. The only rear end available was a 3.08, but swapping in a 3.55 would probably allow them to run with regular GTO's!

Dennis

I believe good believable power numbers for the XV 400 with these cams are:

•Pontiac 066 Cam – 330 hp at 445 lbft torque
•Summit 2800 cam – 340 hp at 440 lbft torque
•Summit 2801 cam – 360 hp at 430 lbft torque (actual uncorrected dyno values)

…with 10.0 to 1 compression and a careful rebuild with torque plates and quality components (pistons, rings, bearings, etc.).

Thanks for following along! It’s been a rewarding journey so far and next spring will tell how it actually performs at the dragstrip.

Dennis

The previous owner weighed the Tempest the one time he had it at the track and it weighed 3650 lbs with him in it and a half tank of gas....he weighs at least 225 lbs, and I'm at 150 lbs, so 3575 lbs with behind the wheel. I plan on swapping it to manual steering which will shed another 30 lbs, so it'll be 3600 lbs with me and a full tank of fuel. That is almost 500 lbs lighter than my '70 Judge (4080 lbs with me)! I wish they put RAIV's in stripper Tempests in '69 and '70...they would have been game changers!

Dennis

Dennis, lovin' the engine results!
3400 reads a hair light to me for a '70 V8 Coupe w PS, esp with near 50lbs of fuel.
The prev 455, did it have E heads & headers? No radio, alum rear drums? Do you have a copy of the '70 AMA sheet where it lists weights? I would have bet another 120-140 lbs.

Thanks Roger! That’s the weight the previous owner showed me on one of the time slips he had from Mason Dixon Dragway (Hagerstown, ND) which has certified NHRA scales. It actually weighed 3680 lbs. with a (claimed) half tank with the 225 lb. driver. Remove the driver weight difference of 75 lbs. and power steering setup (30 lbs.) and I come up with 3575 lbs., then add in 60 lbs. for a full tank of gas and you’re at 3635 lbs. OK, I’ll round it up to 3650 lbs. in case I have a couple of cheeseburgers before the race (haha). I think the AMA weights are on the heavy side and include full fluids including gas. The car weighs pretty much the same as Dan’s 455HO T-37 with the TH400 and basically the same options, except the power steering (30 lbs.) and power brake (drum) booster (8 lbs.). It is certainly going to be weighed again to confirm the actual weight and I will report back in 10 months.

The 462 motor that came in it is a .030 over 400 block with the 4.25” stroke crank, 6X-8 heads with the SD Performance CNC 260/200 cfm port job done to them, Holley 850 on a RPM intake, RAIV clone cam (from Bullet) with 1.50 rockers & regular hyd. lifters, std. RA manifolds (2.25” outlets), 2.5” mandrel bent Pypes X-system with 24” body (huge & heavy) Magnaflow (truck) mufflers, 3.42 posi 12-bolt rearend, TH400 with a Continental Jim Hand tight 10” convertor, std. drum brakes with iron brake drums, all vinyl interior (with the wrong ’70 Chevelle pattern upholstery), AM radio, factory in-dash tach (added) and carpeting which is lighter than the rubber floor mat (Dan’s T-37 came equipped that way too as the original owner knew it was lighter by 10 lbs., or so). The OO didn’t dyno it, but thought 425 – 450 hp to the rear wheels.

The one and only time the OO took it to the dragstrip (Mason Dixon), he drove it from Ashland, VA about 160 miles there and 160 miles back, made 3 passes, two on drag radials he brought in the trunk and rear seat, 1st pass 11.929 at 113.45 mph, 2nd pass 12.082 at 114.85 mph, 3rd pass (on G70 Wide Ovals) 12.301 at 114.65 mph, then drove home. All runs were with the air cleaner on and thru the exhaust. That motor now resides in the ’70 4 door M-20 4-spd LeMans, except with the factory iron intake and Q-jet. That combo ran great down and back to Norwalk (500 mile round trip) and got almost 18 mpg (3.08 gears at 55-65 mph on the back roads driving for economy).

Dennis

….Hagerstown, Maryland...not ND (North Dakota)!

Dennis

That was a great story and a great build. I hope I can get 80% of what you got, in my build.

Greg

Thanks Greg for the compliments! I forgot to mention that the static compression is 9.5 to 1 (even verified that with the Whistler) and the block is zero decked with Felpro 1016 head gaskets (.039" crushed).

Dennis

Dennis , impressive performance and cars , enjoying this thread . I have almost the same motor combo (455/6x heads) in my 71 T37 with similar performance results . Weighed it at Norwalk and was surprised that it was 3890 with me in it . Pwr steering , pwr brakes ac car , just leave it in drive and go , fun to drive .

I love your T-37 Mike. What does it run and what's the running gear?

Dennis

I only made a few runs at Norwalk , my daughter drives/races it also . It went 12.04@113 mph with full exhaust , ra exh manifolds , 3.55 gear , turbo 400 and steel wheels with drag/ street radials . Just has a tci 10 " street converter and just leave it in drive . I have the engine out for some changes , new ring set and going to do a little .more work on heads . Can't just leave things alone , lol .

Nice running T-37 Mike.

Dennis, don't want to clutter up your thread, will catch up w you soon.

Roger, Clutter away...I don't mind since there isn't much going on right now.

Mike, I really am a fan of Canyon Copper and the GT eye brow stripes!

Dennis

the D98 stripes really do look excellent on the canyon copper. I bought a set to try on my castillion bronze T-37 but never got them installed before i sold it.

Roger, attached is the AMA weights for the 1970 A-bodies and the associated weights for my Tempest…
Coupe 23327 3336 lbs.
Turbo H-M (400) 23 lbs.
400 V-8 4-bbl. Engine 245 lbs.
Power Steering 31 lbs.
Power Brakes (Drum Frt.) 9 lbs.
Radio 8 lbs.
Add for 12-Bolt Rear Axle 15 lbs.
Total Estimated AMA Weight 3667 lbs.
Previous Owner Weight 225 lbs.
Total Race Weight 3892 lbs.
Remove 75 lb. driver difference (75 lbs.)
My Race Weight 3817 lbs.

The previous owner ran without the spare and jack, so add another 60 lbs. to his scaled weight of 3680 lbs. = 3740 lbs. with him and a half tank…3801 lbs. with a spare and full tank of gas. Remove my 75 lbs. difference and that equals 3726 lbs. with me behind the wheel with spare and a full tank. So, that probably looks a bit more plausible. Take off the power steering (31 lbs.), half tank of gas (61 lbs.), and the spare/jack (60 lbs.) and the weight drops 152 lbs. to 3574 lbs. (3665 lbs. based on the AMA weights for a 91 lb. discrepancy). I probably made this a lot more confusing than it has to be, but that’s my math and we’ll see next year.

Dennis