DYNO TESTING
The heads were tested on a 455 (now 468) engine mounted on a Super Flow SF-901 dynamometer. Jeff usually does not acknowledge the torque figure at the start of the pull because it could be incorrect. So the reading was taken at 3,900 to get a more realistic number on the 6X head pull. The correction factor for testing was 1.083.

BEST PULL: 6X HEADS WITH Q-JET
RPM....TQ....HP
3,500 524.5 349.5
3,600 514.4 352.6
3,700 518.4 365.2
3,800 521.3 377.1
3,900 522.0 387.6
4,000 521.2 397.0
4,100 517.2 404.0
4,200 502.2 401.6
4,300 495.9 406.0
4,400 504.7 422.8
4,500 509.0 436.1
4,600 506.0 443.2
4,700 497.6 445.3
4,800 494.3 451.7
4,900 486.4 453.8
5,000 471.4 448.8
5,100 457.7 444.4
5,200 455.8 451.3
5,300 451.2 455.4
5,400 439.2 451.5
5,500 427.1 447.2
BEST PULL: KAUFFMAN ALUMINUM HEADS WITH Q-JET
RPM ....TQ....HP
3,500 547.2 364.6
3,600 549.5 376.7
3,700 548.1 386.2
3,800 548.4 396.8
3,900 548.6 407.4
4,000 548.3 417.6
4,100 546.3 426.4
4,200 545.9 436.6
4,300 543.4 444.9
4,400 539.4 451.9
4,500 537.4 460.4
4,600 534.9 468.5
4,700 532.5 476.5
4,800 523.5 478.5
4,900 518.9 484.1
5,000 511.4 486.9
5,100 501.6 487.1
5,200 492.7 487.8
5,300 485.4 489.8
5,400 478.1 491.6
5,500 471.9 494.2
5,600 463.6 494.3

ABOUT THE DYNO ENGINE
Block: .060-over 455 = 468 ci
Crank: Stock nodular iron, 4.21 stroke, rotating assembly balanced
Rods: Crower forged steel, stock 6.625 length
Oiling System: Stock
Pistons: TRW forged, flat-top, exactly-zero deck
Compression Ratio: 9.95:1
Heads: 6X, 2.11/1.77 valves
Mods: Port-matched, cleaned up, bowl work, bigger exhaust valves
Valve Job: Custom, multi angles
Chamber Size: 91 ccs
Head Gasket: Fel-Pro 8518
Rocker Arms: Crane, 1.65:1 roller, Rhoads lifters
Cam: Crower PN 60919, hydraulic
Duration at .050: 231º/240º
Lift: .517/.517 with 1.65:1 rockers
Lobe Separation Angle: 113º
Installed Position: Intake set at 109º centerline
Intake Manifold: OEM '68 cast iron
Mods: Reworked at carb flange to fit both bolt patterns, Q-jet and Holley
Carb: Q-jet, .073 primary jets, .048 custom-machined secondary rods
Carb: Holley, custom .093 primary jets, custom .097 secondary jets
Distributor: GM HEI, 20º mechanical advance
Timing: 30º total, all in by 2,500 rpm
Spark Plugs: AC R45TSX

tqisking wrote:
What would it take for 480-500hp

455 cubic inches
a camshaft in the 246 @ .050 and 253 @ .050 around .500-.550 lift
A good factory intake would be ok but as I said earlier the RPM would be a better choice
A set of good factory heads with a good clean up and valve job(what casting number would depend desired compression ratio)
Cheap 4 tube headers

That is about it you would make 480-500 hp around 5500 rpm maybe a little less..

You do not have to spin the chit out of a engine to make power or be fast you just have to get the combo right

Chad

$2500-$3000

That is all, you will notice that nowhere in here did I say aluminum heads....You will have atleast that kind of money into a sbc and will make nowhere near the tq, so the car will have worse street manners and be slower at the track...Of course if we want it to fall off at 4000rpm he could always put a ford in it

As far as the only 600hp deal, put some compression it it and a more aggressive camshaft profile and you will be at 720-750hp with the same head flow and intake and everything....Ask me how I know;)

Chad

capitlj wrote:
A big block cheaper than a small block!!!!:icon_scratch:
No freaking way not if you're trying to get 400-500 ponies.
The 455 is a pretty potent motor but to get that kind of power you will need some aftermarket heads, intake, headers, cam, and a pretty good carb setup and big block parts are never cheap. I know on the BB ford heads you can machine them out and put bigger valves in to get the flow you need to feed that kind of power but i dont know on the 455. Edelbrock performer RPM's will run you over $800 a piece. I know for a fact that you can get the whole top end kit from edelbrock for a 350 for like $1500 and thats good to about 450 with cam and headers. If you build a stroker like a 383 you can easily push it over 500 hp, but it aint gonna be cheap to get that much out of a small block, or any engine for that matter you have to build it to handle the abuse. You gotta remeber none of these engines were ever meant to push that much power if you cross the line you can get bit in the ass pretty easily. My advise is talk to some guys who have built a couple of 455's the net is a great place for that and do your homework.

WE ARE SAYING THE SAME THING, I said those heads were <u>at least</u> $1600. With all those go fast goodies on that motor it makes 600HP so your guys are saying that those heads, manifolds, and carb are only worth 100hp over the stock ones:eek:. If he spent that kind of cash for 100 ponies, it just doesnt add up to me. You guys are right tho i'm not intimatly familiar with pontiacs (GM ewwwwww) but it don't take that much knowledge to connect the dots. While there are a couple of them on that link that are making 500 with the stock exhaust and heads they have new, or reworked, carbs and intakes as well as completly built valvetrains, and new cams. THATS all i'm saying.

On another note, we will be building a 400 to put in our 75 Trans Am this winter. I'll have to make a thread documenting the build.

tqisking wrote:
You are correct!!!!

The only thing about the RA manifolds is that they are about as good as a set of 3 tube headers (2 center ports are one tube)... So he would be better off getting a cheap set of 4 tube headers, and probably a performer rpm intake. The Q-jet will work fine for 500hp, but will most likely need calibration. It seems though that the person who originally asked this question is not here anymore???

I've heard there are fitment problems with the shaker scoop and a performer rpm intake.

capitlj wrote:
I'm giving up ha not really 5k is not spinning the motor high unless you have a stick or and auto with a shift kit like i dont your tranny will run the motor up to at least 5k before shifting with the pedal to the floor, My 5.0 literally falls on its face after 4k and then i have to wait another thousand RPM before it shifts its frustrating as hell, and that motor for sale is definatly worked over a lot more than what you guys are talking about. I can see aluminum heads, at least $1600, headers on the floor, high rise intake manifold, really shiny fuel pump, and all that makes 600hp. No way you could get over 500 with the stock manifolds, carb, and heads even if they are worked you just wont get the flow through those manifolds. Come on guys i might be wrong but its not for the reasons your giving.

Have you ever seen the size of your exhaust ports on your 5.0?

Anyway if you have a pontiac transmission it will more than likely be calibrated to shift at the correct rpm (low probably 5200rpm dont remember) And you were wrong about the heads they are closer to $2500, and that high rise intake is a victor about the only decent intake that you could buy for a "big" engine untill recently, also that is not a fuel pump it is a regulator...

I am pretty sure nowhere did he say that he wanted to run factory manifolds, did he?

What would it take for 480-500hp

455 cubic inches
a camshaft in the 246 @ .050 and 253 @ .050 around .500-.550 lift
A good factory intake would be ok but as I said earlier the RPM would be a better choice
A set of good factory heads with a good clean up and valve job(what casting number would depend desired compression ratio)
Cheap 4 tube headers

That is about it you would make 480-500 hp around 5500 rpm maybe a little less..

You do not have to spin the chit out of a engine to make power or be fast you just have to get the combo right

Chad

MisterCMK wrote:
I'm done arguing with you. Go read here. http://boyleworks.com/ta400/index.html

All that I am saying is that the RA IV manifolds are supposed to flow as well as a pair of headers. The later quadrajets are up to the task of handling the power. The earlier model q-jets were 750cfm, the later ones are 800. As far as heads go, some of the pontiac heads are great with just a port/polish. The stock parts on pontiac motors have a lot of potential in the hands of someone who knows what they are doing.

You are correct!!!!

The only thing about the RA manifolds is that they are about as good as a set of 3 tube headers (2 center ports are one tube)... So he would be better off getting a cheap set of 4 tube headers, and probably a performer rpm intake. The Q-jet will work fine for 500hp, but will most likely need calibration. It seems though that the person who originally asked this question is not here anymore???

All that I am saying is that the RA IV manifolds are supposed to flow as well as a pair of headers. The later quadrajets are up to the task of handling the power. The earlier model q-jets were 750cfm, the later ones are 800. As far as heads go, some of the pontiac heads are great with just a port/polish. The stock parts on pontiac motors have a lot of potential in the hands of someone who knows what they are doing.

http://forums.performanceyears.com/forums/showthread.php?t=492069

Chad

capitlj wrote:
Big block or not there is no way a stock quadracrap could feed 500 horses it would at least have to be rebuilt for more cfm, and the stock manifolds might get you the numbers but numbers aren't good for anything but bragging. You want that motor to continue building power as the RPM's go up, with stock manifolds it will fall on its face at about 4000-5000 RPM ported or not. Maybe there are some good factory cast iron headers like you get on 89-up 5.0 stangs those might work.

I'm thinking Chad (tqisking) knows a bit about this subject, you might wanna leave the technical aspect of things to him.

Having said that, I still vote for a 2JZ swap.

The motors don't have to spin high to make all their power. They make the power down low.

Seriously though, give it up.

tqisking wrote:
I really wish people would quit calling the pontiac engine a Big Block...it is not all pontiac engines 326-455 are all physically the same size, period....

Yup, like I said.

MisterCMK wrote:
BTW, there is no "big block" or "small block" with the pontiac motors. They are all the same physical size.

This is simple

Take your 400 out ( or buy another block, I may have a couple) Bore it to 4.150 (.030 over)
Buy a eagle 3" main 4.250 stroke crank ($299) buy a set of 6.8" BBC rods and the correct piston for the stroke and rod for a deck height of 10.220". You can buy this rotating assembly balanced and ready to go (besides cleaning) for $2000.00

As far as heads are concerned go and find some 6X -4 castings the -8's are ok also but they are a lower compression, send them to a shop for a street strip port job, I suggest Butler performance in lenoma TN www.jbp-pontiac.com ....They will get you set up, just tell them what you are looking for, I always talk to David Butler, super nice guy and he is very helpfull.

Camshaft just go with a extreme energy from Comp Cams, you will have to know what size engine you are going with first and what the heads flow...

I would try and get a 850 cfm carb on it with a single plane manifold and some 1 7/8" headers if you go with the bigger engine

All in all plan on around $4000-$5000 for 500-550 hp and more tq than you can hook up, nice thing is that you will not have to spin the snot out of it so it will last a long time, but be prepared all that tq will find you weak spots

But what do I know? hehe

Chad

Come back when you learn something about the pontiac motors.

MisterCMK wrote:
You can get a 455 block out of any pontiac. Throw an aftermarket set of heads on there, bore it and stroke it and you're easily over 500hp.
Not quite guy you gotta have a good carb to feed all those cubes and some headers to manage the flow. Plus a good set of aftermarket heads are well over $800 per side. If possible work the stock heads most BB heads can have bigger valves stuffed in then do the engine work should save you a solid $500 but it wont be cheap, and you'll have to do your homework. Best way to do that is to ask guys who have already done it.

MisterCMK wrote:
You can get a 455 block out of any pontiac. Throw an aftermarket set of heads on there, bore it and stroke it and you're easily over 500hp.
QFT.

The only reason the older ones have more power is because of the exhaust, carb and cam. If you plan on swapping that out anyways, might as well pick up any 455 you can.