[OneMeanGTO]

Hey Folks,
I'm restoring a 66 gto hardtop.. Motor is stock 389 with tri-power and M-20 tranny. Looking at maybe using ram air manifolds..worth using them or not? not sure if will go with stock 2.25 collectors or 2.45.. Is it worth going bigger or am i just wasting my money.. what size pipes would you recomended also? should i stay away from flow masterS? heard dynamax ultra flows are good.. thanks

[OneMeanGTO]

Hey Folks,
I'm restoring a 66 gto hardtop.. Motor is stock 389 with tri-power and M-20 tranny. Looking at maybe using ram air manifolds..worth using them or not? not sure if will go with stock 2.25 collectors or 2.45.. Is it worth going bigger or am i just wasting my money.. what size pipes would you recomended also? should i stay away from flow masterS? heard dynamax ultra flows are good.. thanks

[wheelspin]

OMG,

For your stock 389, I don't think you could tell the difference between 2.5" and 2.25". However, plan for the future as reading the Forums will soon have you lusting for "more power".

My signature 66 GTO has Doug's headers, 2.5" X pipe, 2.5" 3 chamber Flows, and 2.5 full length tailpipes. My wife and I drive this car cross country to POCI and GTOAA national events and I dragrace it monthly in the Pontiac Drag Days Series. You need to decide how important "correctness" is and what your objectives for the car are.

Les

[Tom Hand]

If you plan to run it harder later, the larger ones are a good choice. Pipe size of 2.5" should work for a long time.

As far as mufflers, it is really up to your sound preference. With exhaust manifolds, the muffler choice is not quite as critical. The straight-through mufflers tend to allow the engine to make more power when you run it higher. UltraFlo, Xlerator, Magnaflow all will provide very similar performance with slight variations in sound. The chambered and baffled mufflers will also run about the same with the sound level usually being higher.

Chris here at PY has the CD of Muffler Sounds that will let you listen to most of the current popular mufflers before you buy them. It also will let you hear the X-crossover. You should consider putting this on now too and it will help make your muffler choice even less critical.
Tom Hand

[Ccass]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by OneMeanGTO: not sure if will go with stock 2.25 collectors or 2.45.. Is it worth going bigger or am i just wasting my money thanks <HR></BLOCKQUOTE>

HPP Dyno tests showed an overal gain of about 8-12 hp and only a 2hp gain by using the 2.45 manifolds vs the 2.25". Not really worth the extra in my opinion. The mandrel pipes and crossover will make the real difference.

[This message was edited by Ccass on March 17, 2004 at 06:00 PM.]

[ctrumbull]

Dude - I have the same 66 setup as you're explaining and just put on the 2.5" mandrel bent system (w/x) from PY. I wanted as original of a sound as possible, Tom and others previously recommended the Dynomax Turbo mufflers. The sound they give is mellow and very little, which is what I was going for. They let you hear the 389 humm, not some abnoxoius overly-loud muffler. Also, the x-pipe system gives a nice smooth deceleration sound/performance.

Also, I had bad luck with removing the bolts into the exhaust manifold (3 of 4 broke off). Just be careful to use lots of penetrant days and days before if they give you any resistance. Otherwise, the PY system goes on fairly straight forward.

Good luck - Chris

[OneMeanGTO]

thanks for everyones input.. looks like I'm going with 2.5 ram manifolds and 2.5 mandrel bent exhaust.. not sure what mufflers yet.. Cheers!!

[Astock]

I have a brand new set of 2 1/2" R A manifolds that I just bought. I ended up going with Doug's.If your interested I'll sell them at a discount with my receipt.
Jim pocakes@email.com