Originally Posted by
Lille-bror
Thanks guys.
Interesting info. Must take a look on the head bottom and test the engine with another head. We have tried 2 different 9901 pipes and non of them have deformations and no leaks. But I'll keep it in mind.
I'll get it running perfectly. Otherwise its the very first Plus4 with issues!
try a different pipe. the 9901 is nice and smooth, and so is the plus-4. why put them together, i say put a pipe on there that will boost the power a little. i prefer the 9853ss. It gets max power from the plus-4 IMO....also mess around with different headers. I've been really liking the Nova bent headers. 3 lengths to choose from. Great for fine tuning the powerband....and ditch the 6.5mm restrictor if your using that. I always use a 7 or 7.5....and use an Nova plug....Drop the head shimming a little. Sometimes that helps...