Here my setup. 406 with afr 195's and zzx cam. It has a Demon 750 and a victor jr. The compression is 10.4:1.

Ok, I will be spraying 150-200 hp shot on top of that just depending what it'll take to get into the 10's.

To start with it'll be Hooker Super Comp 2210's. 1-3/4" Dia.
The y-pipe will be custom made by me using oval 3" tubing from "spintech" or "burns stainless". The bends will be the prefabbed fittings that they sell. I'll just cut and weld as I need them. The oval 3" tubing is about 2-1/8 - 2-1/4 tall so the ground clearance will be better.

Here's where I need some input.

Should the y-pipe then go into a 4" round pipe all the way back over the axle and then into a straight through muffler or should I go with 4-1/2" oval pipe oval pipe and over the axle. The 4-1/2" oval will fit since it's also only about 2-1/4" tall. The straight through muffler will be built by me.

Keep in mind that I need the least amount of restriction for this because with this engine I dropped a 1/2 second in the 1/8 mile by using cut-outs. The 1-5/8" headers, custom y-pipe, and 3" over the axle pipe with the Flowmaster is very restrictive.

I haven't even sprayed this 406 yet. If I build this exhaust I want this to be as close to uncapped headers as possible. That's the reason for the big tubing. This engine should be able to make 650-675 on spray. I don't plan on using cut-outs anymore. I don't think that the 4-1/2 could be too big since uncapped headers would still flow more.

Any opinions?

 

I am glad somebody has 1/4 mile time differences on a REAL motor between single 3" and free flowing exhaust. Half a second in the 1/8th is A LOT.

 

you know im debating on the same thing... i was thinking of 4 inch round... and a dynomax 4 inch magnum race bullit... just cause its easier.... ill vote for round...