Originally Posted by
Mauve
I run a P4 on 25% so you may even go to a P5 on 30% or the O'Donnell equiv etc. P4 for sure though.
+1 on the P4 and P5, but you have got to
know how to tune. I've even ran a P6 before. The
colder the plug the smaller the tuning window. The
P3 does make it easier for the newer owners of GO
engines to find a descent tune and keeping them
running during the break-in process.