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NOZZLENUT05 · 03-09-2003, 07:25 PM

As some of you are aware, I am building my first project. This has probably been asked before. I plan on building a mild 400/4speed. What are the advantages of headers vs manifolds. Will the R/A manifolds flow equivalent to headers? What headers are "good" and what will fit a 66 gto? I also don't want to deal with the "tick tick tick" noise associated with headers. I am not building a race car, but want to get all that I can get out of the car. Also what exhaust system do you all recommend?
As always thanks for replies.
Josh

NOZZLENUT05 · 03-09-2003, 07:25 PM

As some of you are aware, I am building my first project. This has probably been asked before. I plan on building a mild 400/4speed. What are the advantages of headers vs manifolds. Will the R/A manifolds flow equivalent to headers? What headers are "good" and what will fit a 66 gto? I also don't want to deal with the "tick tick tick" noise associated with headers. I am not building a race car, but want to get all that I can get out of the car. Also what exhaust system do you all recommend?
As always thanks for replies.
Josh

David Jones · 03-09-2003, 07:29 PM

Describe the motor you are putting together.

http://kurtspontiac.homestead.com/DavidJones69GTO.html

goatseeker · 03-09-2003, 07:54 PM

David is right. The more info you can provide, the more advice you'll get back - for better or for worse

.

http://kurtspontiac.homestead.com/TimSimpson66GTO.html

NOZZLENUT05 · 03-09-2003, 09:40 PM

Sorry bout that guys, guess i wasn't thinking completely. What I am putting together is a 68 WT 400 w/16 heads. Motor is being bored 30 over. The heads are being ported to flow better unsure of the flow numbers. My major toss up is the cam choice. I am thinking of putting an 068 cam in, but I like a lopey idle so I was told about the 455? cam. The cam is my major hang up right now. The carb is gonna be the original carb, quad 4 barrel. I think that I am going to try to get as close to 10:1 as possible. Don't want to go under 9.5:1. As of right now there is nothing radical going on, but I am easily swayed to the dark side. Hope this helps.

Ccass · 03-09-2003, 09:53 PM

How often are you going to drive the car? and how often are you planning on going to the track to race? Finally, how fast do you want to go?

NOZZLENUT05 · 03-09-2003, 10:33 PM

Chris,
I don't intend to race the car. But I am also not going to be nice to it either. I want to be able to drive it as often as possible, nice days, cruise nights etc. As far as fast, just like everybody I want to be strong and get down the road as quickly as I can.

axle · 03-09-2003, 11:13 PM

i'm not the most knowledgeable poncho guy on here but i can tell you from my personal experiences and experiments on my pontiac powered 32 ford...the best system i found was using 4 tube headers,2 chamber flow masters,and 2 1/2" exhaust pipe.my engine liked this set up very well! and thats my 2 cents.

Ccass · 03-10-2003, 08:40 AM

I believe a 2 1/2" exhaust system with the mufflers of your choice will do the job. Based on your situation, I would lean toward the RA manifolds instead of the headers because of the long term maintenance issues of a commonly driven street car.

---------------------------
Fool around, Get hurt, don't come crying to me.

David Jones · 03-10-2003, 08:59 AM

R/A manifolds and 2 1/2" pipes.

http://kurtspontiac.homestead.com/DavidJones69GTO.html

Old Man Taylor · 03-10-2003, 11:10 AM

Ditto the above, RA manifolds and 2 1/2" pipes. However, I am concerned about your optimism w/r/t your compression ratio. If you really want to drive it on the street a lot, I would keep it below 9.5:1. If it were my car I would be shooting for closer to 9.0:1 to 9.25:1. Of course I can only get 91 Octane.

http://www.jimspontiac.homestead.com/Index.html

NOZZLENUT05 · 03-10-2003, 01:05 PM

OMT,
I am sure this isn't the area for this question but I figured I would ask it here anyway. Why do you feel that 9.5:1 is too high? ( not being smart, I am trying to learn) I know of some SBC's in the area that are running 10:1. Is my pontiac engine not capable of running 10:1 or even 9.5:1 on pump gas? like I said before this is my first pontiac build up so I am trying to absorb as much info as I can. We can get 93 octane here, so would that make it easier to get 9.5 :1 without detonation?

6567GTO · 03-10-2003, 01:07 PM

Go with the Manifolds. Headers can be a hassle unless you invest in a real good set like Indian Adventures or Doug's Headers.

Axle, You got any pics of your rod? I'm thinking of starting a rod project. I plan on buying a piece here and there over the next several years for a traditional "no billet" rod.

http://home.earthlink.net/~uptons1/

Old Man Taylor · 03-10-2003, 02:36 PM

I hope you can continue to get 93 octane, but I wouldn't bet on it. You won’t lose all that much power by dropping a half point in compression. I would personally prefer to be able to set the distributor curve to what the engine would really like rather than having to tune around a potential detonation problem. Our engines like a lot of advance early in the curve. My streetcar has 9.6:1 with a very large cam, which means less low RPM cylinder pressure. It will still rattle on bad days, i.e., when it is running.

http://www.jimspontiac.homestead.com/Index.html

7072 · 03-10-2003, 07:48 PM

Nozzle,
I just took my 72 to the track for the first time Saturday. Car went 7.95 @ 88mph (1/8 mile). The car has Ram Air manifolds and 2 1/2 inch exhaust, and Q-jet carb. The manifolds should work fine.

NOZZLENUT05 · 03-10-2003, 10:07 PM

Thanks for all the replies. I think that I am going to go with the R/A manifolds. OMT, thanks for the insight to my C/R scenario. I am going to rethink my build up. One again, thanks.
Josh

bonneville Joe · 03-11-2003, 07:22 AM

I just caught something that I don't think anyone else noticed. If you are running 16 heads that motor will probably have quite a bit more than 10:1. 16s are a very high compression head.

Give me a thumbs up, tell me "Nice Car!", but for god's sake, don't call it an Impala.

Old Man Taylor · 03-11-2003, 10:59 AM

Typically a 400 with #16 heads will have a true compression ratio of around 10.25:1. It is very hard to get it down to 9.5:1 without using dished pistons. I got mine down to 9.6:1 by using RAIV valves and a thick head gasket. I also do not mill the heads or the block surface any more than is necessary to get them flat.

http://www.jimspontiac.homestead.com/Index.html

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