Thread: Yet Another Head Question

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I am curious to know from all you experienced engine builders out there how many cc intake runner should a 454 30 or 60 over run. Here is why:

As I just discovered my current 460 is toast, cut oil filter and it has a nice silver metalic color. I am picking up a 60 over 454. It has 840 closed chamber square port heads with stud girdles, full roller, forged crank, 4 bolt, alum howards rods, fulid damper, claims it is around 12:1 compression, cant remember intake, but is set up for a dom.

The motor was in a 79 Z28 with 4:10.1 gear and 29" slick running 11.20 off the brake pedal. I am putting it in a 72 camaro with the same gear and slick w/ 3500 stall. I am prob 200# lighter than the 79Z28, and was wondering what difference a head change would make. I think that a head over 330cc runners will be a bit much for the cid. I was looking to find about a 310 - 325 cc runner.
Am I correct in what I believe?
Please correct me if I am wrong.

you will have to buzz it up with the big heads i do not know how heavy your car is but you may need alot more gear and more stall with them heads and a dom carb a you will have to send it up were it makes hp it would have also to do with the size of the roller cam

Pat, My car is around 3500 with me in it. I was thinking about going 4000 stall, however will run what I have untill funds and necessity make me change it.
As for carb, I have a proform 950 cfm that I will be dropping on the motor for now. The cam he said was around 640 lift. I only had a short phone conversation with him about the motor. I am getting it for $2500. This is very good for me because I would be putting a cover on the car unitl I got funds otherwise.

By the way its a truck block. I heard good things about stroking these things for some nice cid.

have a customer engines .030over 454in a 68or 67 camaro and as dart 320 heads roller cam abit bigger 12to1 4000 stall runs a dom carb and it runs 10.50 with a bad stall and he did not like runing the hi rpm so i regeared it and it fell on it nose . i really did not think it would do that. i think his stall may not be rigth still. but he has a heavy car 3800 and big heads and carb with not much gear with a tall 29 tallslick

Urban, I run a 505 on the street, 10/1 c/r, 291 heads which are basically the same as the 840's, solid roller cam with .655/.663 lift, 250/256 duration at .050. It runs really strong. I realize that we're talking less cubes with your combo, but that's offset somewhat by the fact that you're racing the car, and Im not. I also ran these same heads on a 461 (.030) a couple years ago, and it still had lots of low end torque. Im sure you give up a bit on the low end, but I doubt that it's even noticeable from a seat of the pants feel. Is this a race only car, or a weekend cruizer as well? It sounds like someone put together some good parts. Compression is a bit much for the street, what are you going to run for gas? That might be a problem. Otherwise, sounds pretty good. You would not see a difference going from your 330 runners down to 310, in my opinion. If you were to go to an oval port, now you're talking going to 265/275cc intakes, that's quite a difference. But then you would lose some top end power and rpms cause of the heads. I would stay with what is on it now. They're good heads for sure. If the car runs well as it is, why mess with it. If you can afford a set of good aftermarket heads next year for example, get them with a 310cc runner if that's what you want, and then you would also pick up the advantage of better flow characteristics, better exhaust port flow (BBC's were never known for their good exhaust flow!), etc.. Until then, I say let it be. Also, if this is a truck block as the seller is saying, all that means is that it might have come out of a pick up or suburban. The truck blocks that you are referring to are from big trucks or busses, they are the tall deck blocks. But they are a 366 or 427 c.i. only. They never made a 454 tall deck block. What they did do routinely is use a 4 bolt 454 in the trucks and pickups, and that's a plus. That's what I was lucky enough to find also. However, I dont really need it, and you dont either, a 2 bolt 454 is good to over 600HP without a problem, and lots of people have run them on a race only car for years and years with no issues. But it cant hurt!! I personally am not a fan of the tall deck blocks, only because you have to get a different intake, (or spacers), distributor, and the headers frequently dont fit right because of the added deck hgt. Too many different parts for me. But I realize they have a little more 'meat' to play with, so if that works for an individual, go for it. Good luck with the engine, and let us know what you decide. Pat is good at figuring out these kind of things, and me, well I just do what I can. John

john, thanks for the input. Im glad to hear that you run about the same combination and like it. I have hooker comp headers 2" primary with a 3 1/2 collector out a 3" exhaust. I hope that I dont have too many probs bolting them up. The guy selling the motor says that this is what he was running and had no probs. I am going to leave them in the engine compartment and strap them to frame while I drop in the motor.

As for car use I will be driving it from time to time on the street. I was told I will need 101 octaine. I will follow your advise and not mess with the combo right now and run the 840 heads.

The block is a tall deck though. I was not thrilled at first but now think about a future rebiuld to a 540 cid. should be able to reach 700 hp on pump gas with those cubes.

im glad i found this forum. it looks like there is a lot of knowledge here.
Thanks,
Steve.

hmmm i did no see your post on it saying it a talldeck ? no big deal all the 632 and 572 are tall decks and i did a 526 they work just fine. headers may not work but with the stock gm head you may get by .but not with a hi ex port i build headers so i have been there . on the 12to1 cr i have used in my big blocks with that and over 14to1 on the street . but i try not to do that any more just build bigger engine with less CR so yes you will have to run good gas have the same heads you have on my chevy with a 708 -708 @ 050.268-272 cam that all was on a .030 over 454 now the heads and cam are on a 548

That should work out fine as is, but you should really find out--just so you know for sure--what that engine is. As I said, if he told you 454, that cant really be so. If it was me, I would have to know, that's how I am. The problem with buying something already built is that you really dont know for sure what you have unless the seller has all the paperwork. If you go to buy parts and build on this engine, you're going to have to know for sure what the bore and stroke is, deck hgt, cam specs, pistons and rods, all the particulars. Im sure he will tell you if he's not hiding anything.

the tall deck is easy to tell it will have a 1/8 npt plug buy the china wall on the front of the engine if gm and there is more deck so look at the water pump ports the top bolt hole for the water pump. in the short deck is all most leve with the top of the water pump and a tall deck will have alot more space like 300 inch or so from the deck to the top bolt hole like this has a tall deck 10.200 look at the water pump you can see more space

Urban, I sent you a private msg. So check them out!! John

Pat, good info. That should be pretty easy to spot. I'll have to check that out.

sorry about the pics of my car but that is the only photos i have of a tall deck that you can see it

Pat you said that you build headers. What do you use for stock? New headers cut and changed or do you buy a kit?