[steve]

i got no dyno sim. wouldnt know how to use it anyway. so i need some input.

as you guys know driving around in a flashy vintage pontiac can draw attention and questions. someone always wants to know what your car can do (so they can feel better about their own car). thats cool, i get it.

the problem is that the motor in my car now was not built for power....its a total driver.


still folks want to know and i dont know what to tell them.

can someone run these numbers and tell me what you get ?



72 400 block .030 over.
stock crank and rods
+10cc pistons
7J2 heads (small valve 96cc)
RPM intake
stock valve train
block is NOT zero decked (not sure how far down
they are but if it is critical i can find out.)
rotating assy balanced w/flywheel
hooker headers
de-tuned holley 850 (shaker455)
muncie 4 (wide)
3.91 rear
275/15/60 tires
the cam card is in the pic
what did i leave out ?

what is this engine capable of ? thanks ahead....

[FromTheAshes]

I'm not sure if i got the figures perfect, and this is just a guess with the desktop dyno program but i am getting about (at the flywheel) 315hp at 4500rpm and 400tq from 2000 to 4000rpm.

Which when you subtract the +-15% absorbed by the 4 speed. It's about 270rwhp, which really isn't bad for a street car. Depending on car weight could be very low 14's like 14.1-2 with a 3900+lb car, but below that shouldn't have trouble breaking into the 13's. Note: this is total estimation, using figures the program gives which tend to be fairly accurate from my understanding.

[steve]

thanks man...this is a pretty light firebird i think closer to 3600 but i could be wrong. i have NO accessories and have lightened the load with aluminum a little. wheels, rad, fuel cell, manifolds, ect. so maybe i wouldnt be bragging too much if i said it was a 13.5 car but cant prove it...... yet. that shouldnt hurt any egos either.

[440GP69]

335hp at 4400 and 475tq at 3000

[95ramairformula]

Nice video/nice car by the way. I would say 315/320 hp at the flywheel.
I think the gear is way steep for a 204/214 cam. It will be in and out of the power range really quick with those gears. 4500 rpm and she will be out of power. Don't race anybody pass 60 mph. You bottom end will be real strong. You should have a ton of torque. If you are looking for a cruiser no big deal.

What cam were you running in the video it sure wasn't the 204/214.
The cam in the video hits a nice lope. Sounds like 744 or 041

[steve]

that video was shot when the 421 and RA2 heads were still on the car. it was over 11:1 and had a big mystery cam in it (cold cranking numbers were like 195) you are dead right in the assesment on the car now with the 400. real fun up to about 60-70 and then nothing. the 3.91 rear will stay because this motor is intended to be a cruiser until the stroker motor comes along......thats one of the problems with the looky-loos....the car looks much faster than it is with the fuel cell, 10an fuel system, 3" pipes, tubular uppers. ect. i DO get guys who want to out-run me off the red light. gotta be careful about that. dont want pontiacs lookin bad.

[95ramairformula]

Steve
I had a buddy with a 400 ci, low compression with 6X4 heads, Comp 268H (218/218), turbo 350 automatic, 4.10 gears, headers
in a 75TA. It will take a manual 4th gen LS1 TA or Z28 by a car length to 70 mph then it gets ugly for the 75TA. The LS1 romps all over the 75TA and is about 4 lengths in front and pulling by 100 mph. After a couple of races like that he would let off at 60 while he was still ahead. LOL I told him to bolt on some early heads 72cc and go with a cam in the 224 intake/ 234 range and you will easily take them to 100 mph.
He said hes happy with 0- 60 mph sprint. Anything more than than that then you have to watch for the blue lights LOL.

I will say I am impressed with the low compression power. It will put you back in the seat.

You gotta love that Pontiac TORQUE.

[mchell]

HorsePower TV recently did a stock 400 lo-po rebuild and made around 300hp...not bad

[BVR421]

It only takes one trip to the track and you will know exactly what you have. Get a timeslip and then use one of hundreds of calculators on the web to figure trap mph against car weight and you have your horsepower. Its extremely accurate.
Or just tell people "its about 250hp" and make them feel good about their supposed 600hp car. Just remember when it comes to a bragging contest the first liar aint got a chance. LOL

[69Customs]

I have to agree with BVR421, Take it to the track. Not that expensive. And you'll have fun!