Exhaust flow tube

[Mousehouse1]

How long should they be? I need to make a few of them and need to know how long to make each tube.

[Tony]

I believe six to ten inches of straight pipe is fairly typical of what most people seem to use. Maybe about five diameters ?

[Mousehouse1]

Besides 1 3/4, 1 7/8 & 2" what other sizes should I have made? I mainly deal with small block stuff but would like to get a few sizes for the big blocks.

[Peter]

1 5/8

Any tube size bigger than 1 3/4 will require a spread bolt pattern, so consider that into your tubes.

Peter

[gofaster]

I use a length of exhaust tubing that is 8" to 10" long, with the same diameter and bend as the pipe the motor will run. I may be wrong, but I think the bend influences your port design if the first pipe bend is close to the head. I have seen a slight difference in results between a straight tube and an actual piece of exhaust header on my bench.