[jayls5]

Pontiac 400 block
Performer RPM heads (http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=2439&prmenbr=361)
Forged high compression pistons
performer RPM package (the 1.5k-6.5k rpm one http://www.jegs.com/cgi-bin/ncommer...626&prmenbr=361)
New crank (Not sure if we need a machine shop to balance it or what)
Forged rods, every major component forged, etc

No cats. High flowing exhaust, (probably Hooker)

Turbo 400 tranny.
Stock gears for the time being (2.73's i believe) it's a 78 Trans Am

Pictures/movies/descriptions of the project: Project

If you have any guesses of power output, i'd love to hear it. My friend and I are new to this and we want a general estimate. Please specify Crank/Wheel hp

 

[Frisco]

No guess on your power output. Change those rear gears first. Anything you do to the engine will be a big disappointment if you keep those gears. For all around use go with something in the 3.5-1 ratio. For better performance go somewhat steeper; around 3.73-1 or up to 4.11-1.

 

[jayls5]

We plan on driving it on the street, not all out race.

You couldn't give me a guess even within 50 hp? Just a general range of what to expect.

 

[strikingthematch]

If you want a good idea of what it will make you will have to provide us with better specs.
Such as:
The compression of those "high compression pistons"
Cam spec.
Rocker arm ratio
Carb size,
Type of ing.,
As for the heads I know there is a link but unlike me and maybe you some people have 56k Lol. Add the specs for the heads.
Valve sizes
CC size
Also
Heads size and length
ect... anything that could make a diff. in HP
Also any port jobs done to the heads. If you want good guesses we need good info. If this is all listed at your site sorry but im lazy. lol.
ect... anything that could make a diff. in HP

O and yes you will need to have your assembly balanced if you plan on running an engine making 500HP.


Chris

 

[jayls5]

arg.

Heads: Performer RPM Pontiac, 72cc, Complete, (each)
A 72cc chamber version for high compression, racing applications. Heads have Ram Air IV exhaust port flanges.

Detailed information on the heads can be found here (pretty 56k friendly)
http://www.edelbrock.com/automotive/headpont.html


"Power package": Kit includes matching manifold, carb, and cam & lifters.

camsaft/lifters specs:

Adv. Duration: 308°/320°
Duration @ .050'': 231°/240°
Gross Lift: .313''/.313''
Lobe Seps. 113.5°


Pistons: 400ci Stock-Type Piston, .030'' Overbore
Piston Dia.: 4.150''
Piston Top: -6.7cc Dish, 4-Valve Reliefs
Pressed Pin
Comp Ratio: 10.24:1 w/69cc Heads, 7.16:1 w/114cc Heads
Ring Grooves: 5/64'', 5/64'', 3/16''

(maybe they aren't high compression pistons after all.)

 

[Frisco]

We plan on driving it on the street, not all out race.

This doesn't matter. When you upgrade any engine to performance type figures the HP and Torque curve go up in the RPM range. Without changing the rear gears you would have to run in first or second gear all the time around town in order to keep the engine in the performance RPM range. Even at freeway speeds (60-70) your RPM would be below the power range that the modified engine would run best at.

 

[Garbonzo Bojangles]

I did a quicky dyno run for you. 420 HP @5500 RPM and 442 ft-lbs of torque @ 4500 RPM. Keep in mind that I assumed 1.5:1 rockers and the total combustion space per cylinder was 92.36cc, which is probably very wrong. 144 HP and 377 ft-lbs at 2000 RPM.

 

[Frisco]

EXAMPLE:

2.73 rear gears with 26"diameter rear tires at 60 MPH would be approximately 2174 RPM. This is more than likely well below when the RPM cam begins to come into the power curve.

 

[jayls5]

So you guys suggest some different gears to mend the situation?


I thought power is still made below 1,500 rpm... it would just be very little. It would still drive with 2.73's for the time being until we replaced them right?

Suggestions for the best street gears? 3.73?


Thanks for the help guys.

 

[killerformula]

if this is an all street ride, that is WAY too much cam.

now Im thinking there's something wrong with the post, only .313 lift? Give us a part number or something.


K

 

[jayls5]

http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=109626&prmenbr=361

It's under more details on cam/lifters.


We were just guessing parts that would go well together. My friend posted a thread simply asking what we should do instead of asking if what we chose will work. The edelbrock carb gets in the way of the shaker hood.

 

[Siggy_Freud]

I kinda raised a brow at the lift spec too . . . typo?

 

[jayls5]

Yea, I'd prefer it if an expert on this forum pick out the parts for the engine.

My friend asked the question here:

http://www.hotrodders.com/t48622.html

Links to the specific product would be greatly appreciated.

 

[killerformula]

I think the reason you're not getting the answers you want is that your question is kind-of vague. You want a car that you can drive on the street and make power with is really all I know about this thing. Frisco is right, with any cam you're goign to need more gear. Shoot for a 2500 Stall. 200-215cc intake runners, 72cc chambers with the flat-tops is fine for iron, you could probably push the 64's with aluminum. I think you can do better than the RPM heads for 1700 dollars a pair (that 840 some odd dollar price is for EACH head).

You can run a big cam if you want, but you may have to up the stall. Push up your RPM range and now you're starting to talk about upgrading the springs, valvetrain, rods, oiling system, crankshaft, and things get really expensive past 450 horse/ 5500RPM.

K

 

[Ohio-Dan]

I copied this from Edelbrocks web sight........

----------------------------------------------------------------------------------

422 HP in a 400 Pontiac





Edelbrock Performer RPM Power Package Components for 400 c.i.d. Pontiac:

Edelbrock Performer RPM intake manifold...............................#7156

Edelbrock Performer RPM camshaft kit.............................. ...#7157

Edelbrock Performer Series carburetor (750 cfm, manual choke).........#1407

Edelbrock Performer RPM Pontiac Heads (72cc)..........................#6059

Edelbrock timing set..................................................#7812

Edelbrock valve springs

(included with heads; stock heads use #5757) .........................#5767

Edelbrock retainers (included with heads; stock heads use #9735)......#9736

Edelbrock valve locks (included with heads)...........................#9611



Shortblock Components:
Bore.........................................................4.120" + .030"

Stroke.......................................................3.750" (stock)

Crankshaft...............................................cast (shot peened)

Rods....................factory steel (polished & shot peened-A.R.P. bolts)

Pistons..................................................TRW #L2262F + .030

Rings..Speed-Pro #R9228 + .035 Moly Top-Cast Second (5/64" x 5/64" x 3/16")

Head Gaskets.........................Fel-Pro printoseal w/steel wire #1016



Test Engine Specs:
Main Bearings (clearance)..............Michigan 77 MS 496P (.003" - .0035")

Rod Bearings (clearance)..............Michigan 77 CB 758P (.0025" - .0030")

Piston Wall clearance................................................ .006"

Ring End Gap clearance...................Top ring .018" / Second ring .014"

Rod Side clearance .......................................... .015" - .018"

Compression ratio.....................................................9.6:1

Ignition and timing..............................36° @ 3000 RPM + MSD 6A box

Headers.................1-3/4" primary, 30 long with 3" collector, 12" long



Edelbrock Performer RPM Aluminum Cylinder Head Information:

Intake port volume....................................................215cc

Intake valve size.....................................................2.11"

Exhaust port volume...................................................175cc

Exhaust valve size....................................................1.66"

Combustion chamber size................................................72cc

Rocker arms............................................1.5:1 Roller rockers

Valve Seats cut at.....................................................45°

Material spec........................356 aluminum heat treated to T-6 spec

----------------------------------------------------------------------------------

422HP at 5500, and 441 lb/ft at 4500

According to the graph, the motor is making 380lb/ft at 2500 rpm.

-----------------------------------------------------------------------------------

if this is an all street ride, that is WAY too much cam.

380 lb/ft at 2500. Peak torque, 441 lb/ft at 4500 and peak power at 5500? Seems to be a very good choice for a street driven 400 Pontiac to me..........



I also don't think your gears will be that big of an issue, in a street driven car. Dan

 

[Siggy_Freud]

I am going to disagree with ohio-dan about the gears. Even on a street driven car you wont get the full benefit of having that sort of power without lowering those gears. 2.7 gears are pretty tall. Id suggest 3.52 if your worried about its RPM range while highway driving. It will still give you a decent launch with the right stall.

 

[killerformula]

well I think its safe to say that those cam specs may have a typographical error dan.

K

 

[jayls5]

Hey guys. Since you know more than us, we are basically asking you to present us with the right parts to produce the most power at the least $.

Refer to this thread from here on out:

http://www.hotrodders.com/t48622.html

Thank you all for contributing to this thread so far.

 

[4 Jaw Chuck]

Nice website by the way, here's my favorite video from your main page.

Thats embarrassing!

 

[Ghetto Jet]

Man if one of us posted that in lounge we would be getting read the boards street racing policy by one of the mods. Can we curse here too Chuck?