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