# RAMAIR Mainfolds



## mbspeed (Sep 25, 2012)

Hi guys I have 67 stock style RAMAIR Exhaust manifold's on my 67 468 stroker motor its the stock 2.25 size manifold I have 2 1/2 duel exhaust with X pipe would it be a noticeable difference if I went with the large 2.5 RAMAIR manifolds that RAM AIR RESTROREATIONS MAKE I don't want headers so that would not be an option any info would be great thanks...............Matt


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## GTO1965 (Apr 28, 2014)

I have a 434 (428 bored .030) with Ram Air 2.5 exhaust manifolds with a 2.5 inch exhaust.It's expensive but it did make somewhat of a difference in terms of power but in your case with all those extra cubes of a 468 it will make more of a impact.


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## mbspeed (Sep 25, 2012)

GTO1965 said:


> I have a 434 (428 bored .030) with Ram Air 2.5 exhaust manifolds with a 2.5 inch exhaust.It's expensive but it did make somewhat of a difference in terms of power but in your case with all those extra cubes of a 468 it will make more of a impact.


did you run the stock style first on your 434 before switching to 2.5???atriot:


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## ALKYGTO (Mar 29, 2010)

Would it be possible to port out your existing manifolds to the larger size?


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## GTO1965 (Apr 28, 2014)

Yes I did have stock set up prior. I don't believe I have ever heard of anyone porting out the stock Ram Air manifolds. If you really don't want headers than it's the only way to go but it's not cheap because your switching everything to a 2.5. Jim Hand tested them (2.5) and said they work as well as shorty headers.


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## mbspeed (Sep 25, 2012)

every thing now is 2.5 except the R/A mainfolds that's why I was saying it may not make lot more power only restriction is 1/4 size of inside casting of manifold but lot of guys told me the casting from ramair restoration is better then most other repro R/A s and I got my first set from ames performance and I am installing new ported kre heads so it may be the best time to change even if the size wont help much maybe casting is much better


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## 666bbl (Apr 13, 2014)

Much like step headers, what's wrong with the pipes starting at 2.25 for a foot or so and then open up to 2.5? In fact, if you were to do that you could have the 2.25 run in the center of a 2.5 for 3-5" and get the benefit of an anti-reversion set up, but it would be just the main pipe vs all 4 exhaust ports working in that regard. It would limit spent gasses being pulled back into the cylinders during cam overlap. It wouldn't hinder exhaust performance at all. Just thinking out loud...


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