Hi All, I'm soon finished the rebuild on my Stage 1 to put in my Chevelle so I need to know if a 3" exhuast is too extreme for the engine or should I go with like a 2 1/2" exhaust??
I'm sorry, did you say Stage 1 in a Chevelle? THATS AWESOME! As far as the exhaust question... if its a mild 455, probably a 2.5 ... if you plan to go wild with it in the future and could live with a little loss in low end for the time being... 3.
There is a lot of belief that the 3 inch makes no difference until 500+ HP. I hope that I am not misremembering but I think that view is shared by Dr Weise. The 3 inch is more expensive and louder. At least one friend said because of fit and clearance it was a mistake he would not repeat . He would go with 2.5 next time. I suggest that 2.5 and save the extra money for an x pipe . It will make more hp. to the wheels. See the test below. http://www.boyleworks.com/ta400/psp/exhaust2.html
Yeah I said a Stage 1 in a Chevelle:Brow: as for the enigne I was going to use the TA413 cam but am now getting a custom cam cut at Comp Cams, I'm getting the heads ported and the bowls blended, the springs to match the cam, 3 angle valve job, the block zero decked, the spx intake when its released, long tube headers with an X-pipe and flowmasters. So what do yuou think??
Just do what I did. Go with the Dr. Gas X pipe. I have one that is 3" in front, and 2 1/2" out back into long case Walkers(17749), and 2 1/2" tail pipes. Better flow, and quiet until you stand on it.
I think Eric's got it right. Make your decision based on whether this is it, or if you want options later. My car has 3" with an X pipe. Agree with the expensive comments but changing later costs more than going 3" the first time around, if there's a risk you may want to do that someday. What year Chevelle is this for incidentally? Just curious.
I would also stay with the 2.5 and x-pipe if you are under 500hp. also you could go 3" x pipes and 2.5 tails. unless you really like the sound of flowmasters there are other brands that actually flow alot better. look at goerlich and dynomax ultraflows.
I have three inch header collectors and went with 3" pipe from collector into Dr. Gas X pipe. Mine comes out of the X as a 2 1/2" pipe. (Bonus you don't have to buy any reducers) into large case Magnaflows. I bought mine as a bolt up kit made for the G-body from www.drgas.com I believe they also have A-body kits its just not listed on the website. It goes from header collector to tail pipe tip all mandrel bent. The muffs I had drop shipped from the nearest magnaflow warehouse for cheap. There is a dealer locator on their site. The Magnaflows are a straight thru design like the Walker Ultra flows. Both of which flow better than flowmasters and don't resonate at cruise. They are also quieter at idle and cruise but loud at wot. The bigger and longer the case the quieter without extra restriction. This way you can get the sound you want without restriction. Naturally the flowmaster still flow way better than anything stock and have that pattended sound. My two cents is you are putting a Buick motor in a Chevelle and you plan to have alot of fun with that so why make it sound like every other Mustang and sbc on the road. Best of luck. Check out www.magnaflow.com/02/product/universal/oval.htm
