[robhardy]

mr p body you are a big help. i went back and checked it just says 76 turbo 400. the next line talks about the sway bars and compares them to a t/a. i must not have been paying good attention. thanks on the cam numbers as well. i also noticed that intake is a torquer ii where i said it was a torquer.
i didn't think that those could have been 293 gears turning rpm's like that.
i want to get rid of the dakota digital dash. will the rally gauges screw straight in even though this came with the idiot light gauges? where would be a reputable source for those kinds of parts?

[robhardy]

just went to edelbrock's site. it says that intake is for 3500 to 7500 rpm. i thought i read that it was lower rpm than that. is that really a good match for a big block?
it's also a single plane manifold. that's more of a track design, isn't it?
i've used performers or performer rpm's on all my fords.
i'm not looking to go 150 mph. if i want to do that i'll buy a vette or something that sits a 1/2 inch off the ground.
i'm really curious to see what's inside of this thing. again, i know squat about pontiac engines, so maybe that intake is a better fit than i think. i guess it depends on how it matched the cam and i don't know what that is yet.
sorry about rambling, just thinking that i would have built the engine to start making power before 3500 rpm.

[Mr. P-Body]

Edelbrock's "ratings" for RPM ranges are "suggested", not "in stone". This is particularly true with smaller market engines like the Pontiac. T-2 is the intake of choice for anything over 450 CID with "performance" in mind. We use it exclusively for street engines with ported heads and a "big" cam. The open plenum "softens" the low-end grunt of the bigger Pontiacs, to the point where you can get a semblance of traction. Unlike small blocks, when we say "low-end", we're not talking light-throttle drivability. That NEVER goes away... What we mean is on the "launch" at a dragstrip. Pontiacs are famous for big "wheelies" and blowing the tires off. Neither wheelies nor smoke get you "down the track" as quickly as possible.

When it comes to comparing the Pontiac to any of the Ford or Chevy offerings, there's not much "apples to apples". The 454 can make the torque, but at the cost of high-end power. 460 can, too. The big Ford is a little more "forgiving" where getting low-end AND high-end, than the BBC. Comparing the Pontiac to small blocks, of either "brand" is a mistake. The Pontiac makes the kind of power big blocks make, especially the torque numbers. In short, what you already "know" about engines generally does not "apply". Of course, the fundementals are all the same, but the Pontiac has a unique approach to power. The ability to make massive power at low engine speed is what made GTO the "king" of muscle cars and TransAm the "king" of road cars in their respective eras. It also means a very different "mindset" is required for proper gearing, shifting, tires, etc.

Jim

[Thumpin455]

Mr P is right again. That sound you are hearing is probably spark knock/ping. that can flatten the upper rod bearings real fast and very easy.

The compression is too high for pump gas with flat tops and 64 heads on a 455. The dish works, and depending on where in Alabama you are could be the only solution other than switching to bigger chamber heads like a 5C or 6X. Some places in your state have E85 which with a carb change you could run, but the availability sucks down there. E85 can make some serious power and handle over 13:1 easily, so its a fun option if you can find it. Its everywhere in some states, hard to find in others, Alabama happens to be the latter.

I found that the Ford FE like the 390 and 428 are close to a Pontiac as far as where and how they make power. The Olds is the only other engine even remotely like a Pontiac, and then only the 400/425/455. The 403 and 350 are like the small Pontiacs, but they have a much shorter stroke so they run differently. If you try to do the same things as a 350 sbc or any small Ford to a Pontiac, you are going to have a slow car that gets terrible mileage.

The Torker II works pretty well on a 455, and the Performer RPM wont fit under your hood easily, if I remember right. I know it wont fit a 70-81 Firebird without hood mods, but they will fit a 64-72 GTO easy enough. The only problem I ever had with my T-2 was loading up while driving around town with an 850 Holley on it. My low compression 72 455 HO didnt like it much, but it did fit under the Formula hood on that car.

[robhardy]

Originally Posted by Mr. P-Body

Edelbrock's "ratings" for RPM ranges are "suggested", not "in stone". This is particularly true with smaller market engines like the Pontiac. T-2 is the intake of choice for anything over 450 CID with "performance" in mind. We use it exclusively for street engines with ported heads and a "big" cam. The open plenum "softens" the low-end grunt of the bigger Pontiacs, to the point where you can get a semblance of traction. Unlike small blocks, when we say "low-end", we're not talking light-throttle drivability. That NEVER goes away... What we mean is on the "launch" at a dragstrip. Pontiacs are famous for big "wheelies" and blowing the tires off. Neither wheelies nor smoke get you "down the track" as quickly as possible.

When it comes to comparing the Pontiac to any of the Ford or Chevy offerings, there's not much "apples to apples". The 454 can make the torque, but at the cost of high-end power. 460 can, too. The big Ford is a little more "forgiving" where getting low-end AND high-end, than the BBC. Comparing the Pontiac to small blocks, of either "brand" is a mistake. The Pontiac makes the kind of power big blocks make, especially the torque numbers. In short, what you already "know" about engines generally does not "apply". Of course, the fundementals are all the same, but the Pontiac has a unique approach to power. The ability to make massive power at low engine speed is what made GTO the "king" of muscle cars and TransAm the "king" of road cars in their respective eras. It also means a very different "mindset" is required for proper gearing, shifting, tires, etc.

Jim

thanks, what little i've been able to find has suggested just what you're saying. and the further i get into the car the more i think someone was trying to make a "best of both worlds" car. i had a 59 f 100 that somebody had done the same thing to. had a built 460 a c6. then at some point they started working on the interior. custom dash, stereo, bucket seats etc.
that may be what happened here. on guy built it for the strip and the next guy tried to make a driver out of it and maybe did something stupid and spun a bearing.
so, the thought is that the low end is already so strong on this engine that it actually needs to be tamed to get a good launch and with the mods i'm seeing so far it actually keeps making power at higher rpm's?
from listening i didn't think the cam was all that big but from what i understand roller cams idle smoother that flat tappets, is that right? i've never used anything but flat tappet cams. i really just like street cars and even then i never street race. i haven't lit the tires up on anything on the street since i was a kid. maybe on a country road every now and then but that's it.
even with the knock it doesn't seem to be pinging on 93 octane. the torino had close to 11:1 c/r it pinged but i put hardened exhaust seats and guides in it and played with the timing and it ran like a champ on 93 after that.

[robhardy]

thumpin, i'm pretty sure the performer rpm won't work but i think the performer sits as low as the t ii. i'm going to leave it alone. if i understood him right it makes sense to kind of shift where the power is being made. i'm taking mr p's word as gospel for now. he's had answers i haven't bee able to find anywhere else so far.

[Thumpin455]

That is a good idea, he definitely has the right advice for what works. I was just giving you some info on other parts so you know not to waste your time and money on them. I dont have a first gen, so I can only go by what intake other people say fits without a scoop, and wild ***** guesses. I try to avoid the guesses.

[robhardy]

jim, would a set of '71 h.o. heads solve my c/r issues as easily as dishing the pistons?

[WDCreech]

Originally Posted by robhardy

jim, would a set of '71 h.o. heads solve my c/r issues as easily as dishing the pistons?

I know your question was to Mr. P-Body, but I'll tell you that the '71 HO heads are round port exhaust, so you'll have to get round port headers or exhaust manifolds, probably from R.A.R.E., but they would give you only about 8.4:1 compression unless you had them milled.

Bill

[robhardy]

Originally Posted by WDCreech

I know your question was to Mr. P-Body, but I'll tell you that the '71 HO heads are round port exhaust, so you'll have to get round port headers or exhaust manifolds, probably from R.A.R.E., but they would give you only about 8.4:1 compression unless you had them milled.

Bill

thanks, i knew they were round ports. that sounds a bit anemic even for my purposes. the engine is out but i still don't know what it looks like inside. i may find myself hunting a block instead of heads.

[robhardy]

looks like the 66 castings had d ports. those were the 325 hp heads in 71. any thoughts on the performance of those?

[Thumpin455]

If you want to do a head swap to lower the CR, you want 6X-4, 5C from a 400, 96, or 7K3. The 7K3 will need manifolds or adapters because the end exhaust bolt holes are not there and there is no material to drill. They are big valve heads with guide plates. The 96 is from a 1971 400 and they are big valve low compression heads. The others have a 1.66" exhaust valve, which really doesnt hurt much on the street.

If you dont mind getting some work done to the heads, you can use certain 350 heads. The 1971 vintage 350 head, I think the casting number is 46 or 47, have the right size chambers for just over 9:1 on a 455, but they are small valve heads, some have screw in studs some dont. You can have them ported, bigger valves installed and screw in studs installed if they dont have them. They will work just like any other D port head that has been ported.

Also other heads that have pressed in studs but will work are 15 heads, they were the low performance 455 head in 1970. All of these are D port heads, and while round port heads will work great, even the HO heads they are more expensive and require more expensive headers or manifolds.

You want around a 90cc chamber, give or take a little depending on deck height, to run pump gas. I had some machine shop ported 5C heads on a 455 and it ran very well on 87 octane, no ping at all, and it had a 224-230 cam in it with a Qjet. 13.50s @105 with 2.93 gears, stock converter in a 4100lb car with traction issues isnt too bad for a low compression engine.

Those 64 heads will work great on a 400, puts the compression right around 9.5 with a zero deck.

Otherwise, pull the engine down and install dished pistons. To me a head swap is easier, and a fuel change is easier still, if you can find it.

[cdminter59]

Originally Posted by robhardy

just went to edelbrock's site. it says that intake is for 3500 to 7500 rpm. i thought i read that it was lower rpm than that. is that really a good match for a big block?
it's also a single plane manifold. that's more of a track design, isn't it?
i've used performers or performer rpm's on all my fords.
i'm not looking to go 150 mph. if i want to do that i'll buy a vette or something that sits a 1/2 inch off the ground.
i'm really curious to see what's inside of this thing. again, i know squat about pontiac engines, so maybe that intake is a better fit than i think. i guess it depends on how it matched the cam and i don't know what that is yet.
sorry about rambling, just thinking that i would have built the engine to start making power before 3500 rpm.

I checked on the Torker II it is a single plane intake with an operating range of 2500-6500 rpms. Too bad you don't live near Virginia my nephew has a couple of 400 blocks and he has a complete 455 motor, that I don't think he would part with it. I think he said it was kind of rare.

[robhardy]

Originally Posted by cdminter59

I checked on the Torker II it is a single plane intake with an operating range of 2500-6500 rpms. Too bad you don't live near Virginia my nephew has a couple of 400 blocks and he has a complete 455 motor, that I don't think he would part with it. I think he said it was kind of rare.

the 455 i have is rare. the problem is it doesn't like pump gas. i'm just looking to de-tune it a little. it's starting to sound like the dished pistons may be the easiest fix.

[robhardy]

30 over crank is 20 under. tops of rod bearings are bad. Jim pretty much called it. detonation. i'm probably going to sell it and might put a 350 back in it and start restoring the car to what it actually is. a 69 firebird 350.