what size exhaust?

Hey guys,

I'm working on getting my 68 street legal. As you can see in my sig I have a 468 in it with 11 1/2 to 1 compression and a 1050 Dominator carb. My question is what size exhaust should I run? I was thinking of 4" but I think I'm gonna have a hard time finding anyone around here that can work with that big of a pipe. I was planning on dumping the exhaust right out of the muffler too. I was looking at the Borla XR-1 oval and the Flowmaster original 40 series. I'm not worried about the sound level. The louder the better. :D Give me all you guys opinions.

Thanks as always,
Bubba

Unless the mufflers flow as much as the pipe, they just look like a "plug" to the flow.

Personally, I don't believe Flowmaster's flow as well as say Dynomax Ultraflow welded.

http://www.dynomax.com/ultrafloweld.stm

There are a few Magnaflows which are similar in construction which should flow about the same. The Borla XR-1 Shootout race muffler @$300 per. has a 4.5 inlet and outlet and flows probably more than your engine needs.

Unless you have a 900++ hp engine, I'd suggest headers with 3-1/2 outlets and 3-1/2 inch pipes back to the mufflers. You could then expand into the 4-1/2 dia to fit the Borlas, and get about zero loss, but TONS of noise.

I think a better idea would be 3 inch ID high flow mufflers like the ones I mentioned, and use a long (12 to 18 inch) transition from 3-1/2 to 3 inches just before the 3 inch inlet muffler. A 3 inch turn down at the outlet would be good.

With the Borla you'd be looking at something like $750 from the headers back (not stainless tubing either), and with the Ultraflow welded maybe $250. Somewhat quieter, too, but still PLENTY of noise!

My $.02

3.5" all the way back. Most shops have no problem with this. If your not concerned about sound levels, skip the muffler, untill inspection that is.-

Thanks alot guys. I'm going to see what I can get done.