Hi folks. Since it is winter up north and so therefore time to clean the boats after the summer, I noticed that my header was about an inch plus passed the second "O" ring in the pipe. It is a stock 26 with a 2 inch band pipe. The motor was turning 15640 RPM. I was understanding that the header should not go past the second "O" by more than about a 1/2 inch or so. Should I cut more off the header now that it is off the motor or would it be OK left like it is? The motor ran real good this year with no problems.

Any suggestions or help would be great.

Regards
Tar

Normally after I have found the sweet spot on mine I will cut it. It is said by some that the longer header (even if sticking into the chamber) will add extra torque and cutting it down helps top end to the detriment of torque. This would theoretically be the case even if the overall tuned length was not changed. I have never done any conclusive testing on this myself though. I usually stay on the conservative side and try to leave about 1/2" past the Orings. Maybe if I have some spare time this winter I will do some dyno pulls to try and see what the impacts are. Maybe Scott has some input on this too?

Key point to keep in mind is that your length you have settled for is NOT too short ?

If on the other hand your prop of choice is on boat, you have fooled with length enough to be satisfied your in the SWEET SPOT, then DO CUT EXCESS HEADER to within 1/4 -3/8" of the back o-ring.

* Closer the headers cut end is too the tip of divergent cone, better the scavenging will be on the return/ boost wave headed back down the header towards ex port.

If the header is only passed the 2nd o-ring about 1/2 or so... i myself would not worry about it, especially if you are using an aluminum header.. as if you happen to loose water flow to the cooling ring on the pipe and the o-rings burn grooves into the header, you will have that little bit of room to pull the back out so the o-rings will seal and still maintain around the same performance.


Its really up to you though. That RPM sounds about right on for a stock 260 with an aluminum band pipe (and going by your avatar picture im assuming its in a mono). My old mono with stock 260 and steel pipe turned 15930-15960 consistently.

Thanks folks for the replys. Yes it is in a mono and has a SS header. I was running an ABC 2716 and turned a 56.1 MPH, at the above RPM. I think that I did indeed find the sweet spot. I am not a racer though. I will cut it shorter this winter.

Thanks again

Tar