[jeff chmura]

Hi Guys,
I picked up a '65 a few months back. It has the original 389 in it. I took it out and I have a '65 389 from a grand prix I'm going to use for the time being.
Anyways, my question is headers or exhaust manifolds.
It has headers installed, but there worn out and need to be replaced. The headers were a bear to get to to unbolt, plus they hang low, I was thinking of the RA III style manifolds.
Any feedback about what your using would be great
The PO installed a turbo 400 trans and a 12 bolt rear from a 70 chevelle. The rear is posi with 3.07 gears, a little low for my taste, may change it to the 3.55-3.73 down the road.
I am going to use this as a driver and enjoy it.

Thanks Jeff

[b-man]

Exhaust manifolds all the way.

On a street cruiser with a near-stock engine there's really no point putting up with the hassle of running headers.

Even the standard log manifolds work well and will be down less than 10 HP compared to the RA manifolds.

Right now building up a stock 370 HP '64 421 HO and will be running log manifolds on it, for my 1964 LeMans convertible.

If you do any highway driving you'll soon fall in love with those 3.07 gears.

[GT182]

I agree with Bart... exhaust manifolds all the way.

Headers are a PITA and won't last nearly as long as cast iron manifolds will. But that's only my opinion.

[jeff chmura]

Thanks for the info B-man
The original engine had headers installed, and what a PITA to get the manifold bolts out.
I don't have GTO manifolds,I do have the GP manifolds, but I think there different because there full size, so I have to get something. I was thinking about these....
http://www.ebay.com/itm/1964-73-Pont...44c745&vxp=mtr
or these...
http://www.ebay.com/itm/Pontiac-Ram-...b89a94&vxp=mtr
I'm wondering how well they seal to the head.

Thanks Jeff

[b-man]

Get the ones specific to '64 -'67, they seal up fine with the fewer bolts. Interesting fact is 1965 GTO engines only came with 4 bolts holding the manifolds on even though the heads and manifolds had provisions for 6. The 2 outer bolts were not used.

If the GP manifolds are rear exit they will work, but usually the drivers side has a center outlet on big Pontiacs and won't work.

[jeff chmura]

Thanks b-man
one has the center outlet,off the top of my head, i don't remember what side.
Thanks again, Jeff

[OCMDGTO]

Manifolds get my vote. I had headers on my old 70 GTO & they were a huge pain. I got tired of constantly changing leaky gaskets & replacing them due to crushed tubes from speed bumps & bottoming out while burning up the back roads. They did not add any power like I was hoping for, either. It was a mild 400 car that I drove at least 100k miles. When I got my 69, one of the first things I did was take the headers off & put the RA manifolds on. No regrets there. Obviously the racers will have a different opinion.

[jeff chmura]

Thanks for all the help guys, RA manifolds it is then.... Jeff

[Vet65te]

I added Hooker Headers to my 64 GTO back when I was installing the engine. What a royal pain. And when finally installed, as already mentioned, one side collector hangs down much further than the other. Never again.

[rexus31]

I bought my RA Manifolds from these guys. I'm running a '68 400 in my '64 GTO.

http://www.ramairrestoration.com/rm-...oversized.html

[Rapdron]

Hi Jeff
It's not exactly the same, but i put on a set of long branch manifolds on my 66 2+2.
Best exhaust option Pontiac ever made. Sound and fit great, don't loosen up like headers.
For a street car, those Ram Air manifolds for your A body would be my choice for ease of installation and fit.

Ron

[GTOLiam]

I just purchased a set of RA manifolds after spending a silly amount of time unbolting a set of Hooker ceramic coated headers to get the engine out. They won't go back on my car and they're up for sale

[jeff chmura]

Well, It looks like we all have the same feelings on the headers. The ones I removed were rubbed flat from hitting the ground and a PITA to get off when I pulled the motor.
I appreciate all the help about the RA manifolds. i was a little concerned about fitment in my '65 , but it looks like a good fit.
Whats the difference between the 2.25 and the 2.5? I can't see any HP gain there. What size are you guys using, 2.25?

Thanks again, Jeff

[Old Man Taylor]

I ran that setup about 40 years ago on my '64 GTO. There was no choice then as to the outlet, so mine was 2 1/4" outlet with a stock '67 exhaust system, also 2 1/4". If I were to do it today, I would go with the complete 2.5" system. As you said, the fit will be good on your '64, but you will have to move the brake fitting (distribution block) on the side of the frame on the driver's side. I just bent mine up and out of the way.

[The Champ]

I used the RARE RA manifolds on my '64 and went with the 2.5" outlets as I ran a 2.5" exhaust all the way back.

[elefantrider]

I run standard '65 logs on mine with mandrel bent down tubes. I just removed the heat riser and plugged it with freeze plugs. Flows very good! You can find a set of '65 logs for $100-150. The price of the RA manifolds on ebay are only the beginning, you need the bolt kit, studs, cast collar, down tubes too. $$$$$

IMHO, RA logs do not look right on a '65.