No Ordinary 91

I have heard that on the seimesed runners you can cut the cast wall inside the runners back increasing plenum volume and shortening runner length. Supposidly bumping power up as much as 800 rpms. Is there any truth to this i am looking at upgrading runners and can't decide if i want to go large tube or siemesed. If this would actually work i would prefer to go this route since they are a bit cheaper and look cooler

Aggravated4life

You can port the siam.runners fairly much with some porting tools but its a bit o' work.Theres quite a bit of meat on them you can remove and I believe they can be made to flow much better then most or all large tube runners on the market except the SR system.
It cant hurt either...If you havent seen the picture, go to the engine mods on this forum, and theres a topic there with a jpeg you can see..(i made the topic there)its the more extreme porting job to the siam. runner, in which the person cut the back off it and ported everything down in there and will need to re weld.
I imagine it will flow alot when all is done.

88sk

got alot of siameserunner info from http://www.thirdgen.org its a camaro- firebird site same mods as vettes, do a search.. :eek: