Thank you for replying.
I am not unhappy really with the performance of the stock set up, but I never mind losing some weight. It runs like a champ and comes out of the hole really good, and I'm ok with the top end speed, running a 19 SS prop for skiing.
Also this engine has an unusual behavior when I run it at high rpms. The temp gauge climbs around the 200+ region. Generally 4K and above. I've laser temp checked everything when it does this and the block itself actually is running cool, at around 140. The manifold temp sensor though is truly running that hot. I've changed all usual suspect components, including exhaust manifolds and risers per Mercruiser troubleshooting, and this fall had the outdrive off and changed all cooling components there. This is an older version with 1" intake as opposed to the 1.25 that VP superseded to, but I've been told that should not make a difference on the 4.3.
At this point I'm wondering if there is perhaps a casting flaw in the manifold that is restricting circulation at high rpm's, or there is air getting trapped in there at high rpms.
