Crossflow genius's needed

[Bob.T]

I'm in the midst of completely renovating my ride and rebuilding my 1979 Johnson.I got a copy of the '11pages' and have done some porting and 'flowing".A buddy gave me heads and carbs from a 235 that he says will help. However when I compared the 235 head casting numbers they were the same as my 175 heads.Did the factory simply cut them for the 235 to get more power?I also under stand that the factory used tuner length to limit horse power.The 175 tuner is ~7' long and the picture in my manual shows the 235 tuner as being a lot shorter.Is ther power to be gained by cutting my tuner ?If so ,how much should I cut? Thanks a bunch! BT

[racer]

Exhaust system on a 235 and your 175 are completely different thus you cannot compare tuner length. The heads should be different but many were changed to the 235 version, what number do you have?

[Bob.T]

Thanks for the reply ,Racer.I realize that the 235 bubble backs were different,however,as I said,Iwas curious if shortening the tuner would help.I read some of the tech in my old Hot Boat magazines and there was discussion about shortening the tuner on a V4 in order to increase power. Both sets of heads have the same part nuumber,328325,328324.Thanks for your help with my old dinosaur!! BT

[racer]

Shortning will hurt low end and very minimal top change, tuner length is affected by how the tuner is feed. 78/9 235 heads end in 872/3

[Bob.T]

Racer,thanks for your help!! BT