Offenhauser intake /carb problems
 

Two years ago I had a 350 ci engine for my Donzi restoration built, and unfortunately the engine builder is no longer in existance. I have finally put the engine in the boat and have been trying to get it to work but to no avail.
It will rev fine when not under load (attached to hose) but when its in the water it bogs down. I had TPC build carbs for it. They were modified 650's. The jets were 69 on the primary and 76 on the secondaries. I tried to lower these but still get too much fuel. (I believe). The plugs are all black from a way too rich condition.
The specs on the engine that I have are the following.

Compression on Pistons – 10:1
CC Chamber on Head – 72cc
Intake Runner - 18cc
Lift on Cam – 515
Duration – 246 Degrees @ .050”
Roller Rockers – 1.5

I have been told to can the Offy manifold and go to a Edelbrock performer, but I love the look of this setup if it can work. Any suggestions


http://www2.hotboat.com/image_center...gine_1-med.JPG

Thanks.