Exhaust Cut-Out Performance

So if y'all saw my previous post, you know I installed an exhaust cut out on my '83 K20 a month or so ago. Two to one exhaust, long tube headers, reworked 906 heads, vortec intake and a Summit 1103 cam. Been a blast cruising in the ol' girl!

Love having the 'fun switch' for some light strip cruising, and she sure garners a lot of attention when I do! lol

Here's something I learned though. Opening the cutout cuts torque SIGNIFICANTLY! I can really feel the torque drop when I'm on a country road by myself and stomp it. She takes a little longer to get up to speed, but then the power comes back on with a vengeance at the top end.

I had read that open headers would kill torque on the low side, but bring the HP back harder on the top end, so it's kinda fun seeing the science in action.

Anyway, happy cruisin!

Check out some the exhaust episodes of engine masters. While not an apples to apples comparison, their test did explain some of the myths and theories of exhaust.

Matt69olds said:

Check out some the exhaust episodes of engine masters. While not an apples to apples comparison, their test did explain some of the myths and theories of exhaust.

Click to expand...

I'll take a look, thanks!

Exhaust scavenging is a very real thing, My 76 there is a very noticeable difference between open headers and with exhaust. Loses all of its low end with open headers.

That is one of the reasons that real race headers have much longer collectors than street headers, it provides some scavenging. So if one was to run open headers with regular headers, 12" of pipe after the collectors will probably make a difference and for the better.