[4mula73]

Hey all, I'm about to start assembling my 400 for my Formula. Here is my buildup:
#500557 (yes I know) 400 .030" over, decked .010"
Stock (.020M .030R) 3.75" crank and reconditioned 6.625" rods
TRW forged flat tops (6.70cc)
1971 96 heads- gasket match and smooth runners, no porting. They cc'd at 100cc. Right at 8:1SCR
Edelbrock Performer- gasket match and separate coolant x-over
73 rebuilt 750 Q-jet tuned as per Cliff's book and advice
Comp Cams XE256H 110LSA 212,218@.050 .453,.461 w/ Magnum 1.52 roller tips
Melling roller timing set
Performance Distributors DUI w/ custom advance curve and Livewires
RARE HO/RA oversized D-port exhaust manifolds with 2.5" dual exhaust, no x- or h-pipe

Any guesses on HP and torque? Granted it will be a daily driver, I'm not wanting a hot cam. My guess is about 320HP and 420lb/ft at the flywheel. Is that too optimistic or too modest? What do you guys think? Thanks

[LATECH]

My guess is about the same. 300 hp 390 torque
compression is a tad low, cam is small. both work OK together ,but not to the best efficiency as far as making power. Should be low octane friendly

[4mula73]

I think it will run similar to an 068 cammed motor

[Poncho-V]

Plugged your numbers into Desktop Dyno and got 331 peak HP @ 4500 and 450 peak tq. @ 3000. Nice low octane street cruiser!!! Very close to your guesstimate!!!

[Skip Fix]

About what is in the '81 TA now except I have a Summit 2801 cam-but 0.050 is close.6X-4s with some pocket work and 1.77 exhausts. Also has dual cats in the exhaust after the H pipe to clean up the idle HCs when it had to have a sniffer.

With a really tight factory convertor that bogged at the line with the 3.08s high 14s. It has a little looser 13" Continetal now but I have not taken it back to the track since I added it. I'd guess mid 14s in the 3900lber now maybe better.

[Baron Von Zeppelin]

Sounds like almost same recipe as a 1971 YS/96 400 - they rated about 300 hp via PMD.
Except you'll have better carb tune and better exhaust.

If you have not already bought the cam - or can exchange it - you will never regret going to more along the #744 grind. Approx .425 lift intake / .465 exhaust ... with better LSA for low compression / pump gas.

068 range cams are just no fun at all really.
With Rhoads lifters , the 744 will idle just like an 068

With optimum ignition and carb tune , will "feel" closer to 400 hp in the driver seat if you have at least a 3.23 rear.

[4mula73]

I am using a 3.23 to keep RPMs down because it has a TH400 and it will see highway miles. I already have the cam. I chose it because I wanted torque right off idle. Baron, I do see what you are saying however. Not a bad idea.

[Baron Von Zeppelin]

We did about a dozen 400 builds for pump gas daily drivers in the 80's and 90's .
Some i did start to finish , some just sold parts to and advised.
More in the 9.0 - 9.50 CR range tho.
We drove these cars daily - everywhere - everyday - in those days .

The guys who went 068'ish were eating dust and debris.
The difference from 068 to 744 is practically amazing ... to us simpler folks.

3.23 Auto A/C 2nd Gen Bird 400cid with that arrangement will roast tires from dead stop without power braking. Plenty of torque. Dangerous power for rookie'ish drivers .
But they enjoyed the learning curve and loved their cars again .

Going from 2.73-3.08 with around 200hp - to what we put in them - was a completely different car. Fun days back then . i just WANNA GO BACK

Just trying to tell you ... 068 is for trailer queens / show-shine cars.
No sin , just less fun .

[zeebo]

Originally Posted by Baron Von Zeppelin

We did about a dozen 400 builds for pump gas daily drivers in the 80's and 90's .
Some i did start to finish , some just sold parts to and advised.
More in the 9.0 - 9.50 CR range tho.
We drove these cars daily - everywhere - everyday - in those days .

The guys who went 068'ish were eating dust and debris.
The difference from 068 to 744 is practically amazing ... to us simpler folks.

3.23 Auto A/C 2nd Gen Bird 400cid with that arrangement will roast tires from dead stop without power braking. Plenty of torque. Dangerous power for rookie'ish drivers .
But they enjoyed the learning curve and loved their cars again .

Going from 2.73-3.08 with around 200hp - to what we put in them - was a completely different car. Fun days back then . i just WANNA GO BACK

Just trying to tell you ... 068 is for trailer queens / show-shine cars.
No sin , just less fun .

sounds good..but question for you--what cam to run with my combo--?

73 lemans 2.93 posi th400 mild shift kit stock stall
400 stock bottom end...1970 #13 heads at 75cc..compression approx 9.6:1
stock 73 4bbl intake, qjet calibrated and points dist curved.

would a 744 cam or the summit 2801 give me the low end and midrange torque to smoke some tire? or would another cam be better suited? oh and btw..are these cams run with 1.5 or 1.65 rocker arms? thanks!!

[4mula73]

Baron, my setup will still have some of tire roasting power though, right? This is my first car so I didn't want too much power. Won't it still be fun to a novice though?

[Baron Von Zeppelin]

Originally Posted by 4mula73

Baron, my setup will still have some of tire roasting power though, right? This is my first car so I didn't want too much power. Won't it still be fun to a novice though?

You'll get bored quick.

Unless ... you mean its your first car ever on the road ? (like 16 ?)
In that case - may take a year or so before you're chomping for mo powah

it would be more power than i would want to put a 16 yo in charge of right away.
068 range is even pushing it some.

[4mula73]

Yes I am 16 but no it isn't my "first" car. I drive a 94 Ranger 5spd to work everyday so I'm sure there will be a huge difference from what I'm used to. I don't plan on dogging or racing the car, I just want a little more than stock.

[Baron Von Zeppelin]

Originally Posted by zeebo

400 stock bottom end...1970 #13 heads at 75cc..compression approx 9.6:1
stock 73 4bbl intake, qjet calibrated and points dist curved.

The last one we did ... was almost duplicate of yours.
13 heads , 73 Intake and Carb from a fullsize 455 (EGR needed in 76 Formula for DMV visual smog inspection)
Carb untouched other than a Delco kit and screw adjustments - stock Electronic Distributor calibrated with HO Racing kit.

350 Tranny with Shift kit - stock convertor.
Car screamed from bottom to the top.
Scared the 20yo owner almost to death.

It was previously a 350 2bbl with single exhaust and single trac 2.73
It got 3.23 posi with true duals with dual cat convertors in the build process.
Car changed a lot - he was more than amazed .

But - we always used Rhoads lifters in the Automatics.

And i don't know for sure how the 2.92 will pull off initially - convertor might help - i'm no convertor/auto tranny guru. We always went 3.23 or better on these builds.
2.92 is not so far off - and the lifters will tame 744 to 068 status until rpms rise .
Probably workable with 2.92
Might even help it be less crazy under full throttle out of the hole..
No real world data for you though.




would a 744 cam or the summit 2801 give me the low end and midrange torque to smoke some tire? or would another cam be better suited? oh and btw..are these cams run with 1.5 or 1.65 rocker arms? thanks!!

With Rhoads lifters - you should have it all bottom to top with a 744.
The power these builds made was comparable to my bone stock virgin 73 SD 455 TA Auto with AC and 3.08 gear. i was impressed right away.

At the very most with 2.92 - you 'might' (might not) need a quick step on the brake pedal for half a second or so , to melt tires from a dead git . Wish i could be more specific ... but we never did a 2.92 car

We always went with 1.5 rockers.
One build the guy did slot the pushrod openings to allow for 1.65 if he wanted to later. He never bothered with that experiment.

i will never build a Pontiac with anything less than 744 range cam.
Have sampled rides in many well built 068 range cars.
Its a waste of free horsepower without any other changes from an 068 build - except for the Rhoads lifters in an Automatic 400.
Big Bores probably wont need variable lifters.

Back then good rods were $500-800 to feel safe with a 455 you intended to beat on.
400's were the flavor of choice.
We were a bit nieve and total builds were usually $1000 or less with fresh bore.
Good rods were too much $ for young men back then .

Degree'ing the cams is crucial . You never know for sure until its verified.

Replies above in red text.
Hope it helps some.

[Nicks67GTO]

At 16 years old I was thrashing my current 67' GTO with a 360hp 400/4 speed and wanting more. The first car I drove was a 300hp 350 in a 70 chevelle. That thing was a turd compared to my HO GTO. Just sayin....

[zeebo]

thanks Baron..yeah, im looking at the summit 2802 cam as well as the crane 283801 cam--and others in that range of duration/lift..im hoping to not over cam for my application and have good low end and midrange torque too..its not a race car, but id like a cam that gives me good street manners and has a fairly lopey idle.

[Baron Von Zeppelin]

Originally Posted by zeebo

thanks Baron..yeah, im looking at the summit 2802 cam as well as the crane 283801 cam--and others in that range of duration/lift..im hoping to not over cam for my application and have good low end and midrange torque too..its not a race car, but id like a cam that gives me good street manners and has a fairly lopey idle.

i would think more along the 2801 range if going Summit - and thats with Rhoads lifters too.
For characteristics that you want and describe.

Rhoads will drop lift at idle/off idle by about 4-5%
.425 becomes about .405

2.93 with tight 400 THM convertor - you want about .400 - .410 intake lift at idle/off idle at the most to meet your wishes. My opinion through hands on , anyway .

[Baron Von Zeppelin]

Originally Posted by Nicks67GTO

At 16 years old I was thrashing my current 67' GTO with a 360hp 400/4 speed and wanting more. ...

One of my best friends had a Red 67 4spd HO with fresh rebuild waiting on him before he even got his learners permit. lol
His ol man would take us out on Sundays and let us drive it while he waited to turn 16.
My friend quickly became the best driver of all of us - and he still is.

None of the rest of us had a dad quite like that back then.
Or a car like that either . i had a Vega GT

I have an almost carbon copy of his old 67, now.

[zeebo]

Originally Posted by Baron Von Zeppelin

i would think more along the 2801 range if going Summit - and thats with Rhoads lifters too.
For characteristics that you want and describe.

Rhoads will drop lift at idle/off idle by about 4-5%
.425 becomes about .405

2.93 with tight 400 THM convertor - you want about .400 - .410 intake lift at idle/off idle at the most to meet your wishes. My opinion through hands on , anyway .

thanks for the help--im considering all options, especially from builders, as this will be my first pontiac build. i am considering a continental 13" converter, and other cams as well... possibly that 744 cam you described above..

[zeebo]

Originally Posted by Baron Von Zeppelin

One of my best friends had a Red 67 4spd HO with fresh rebuild waiting on him before he even got his learners permit. lol
His ol man would take us out on Sundays and let us drive it while he waited to turn 16.
My friend quickly became the best driver of all of us - and he still is.

None of the rest of us had a dad quite like that back then.
Or a car like that either . i had a Vega GT

I have an almost carbon copy of his old 67, now.

you guys are the luckiest go grow up in that era..that wont be seen again for 1000 years....im so jealous..i needed to have been born 15-20 yrs earlier....

[PunchT37]

You`re close on your estimate. It will run out of power early with that 256 seat timing on 400 cubes though. Well, at least the stock rods will have a chance.

Should be fun to 4200 rpm`s or so. We`ll see what happens later after you get used to it.

Gotta say, not bad for 16 yrs. old.