I have an 496 Mag base (375hp) that drives a jet boat. I have an old Banks TT draw through setup from a 454 that I would like to bolt on to it. It has 1/2" holes bored in the turbine to limit the boost to 6-8psi on a 454, I am guessing that it may be a little higher on the 496. Turbocharger(Hugh MacInnes) book indicates its a good fit. I would ditch the carb and connect the intercooler to feed the TB.

My Question of the day: I would like to plug the turbine holes and run 35mm external wastegate to reduce lag and have adjustable boost if it looks like I can safely wrap/shield the pipes as they are an inboard boat situation.

 

A slight progress update: I have made 2ea SS spacers to fit between the water jacketed cooled exhaust manifolds and the sweeping right angle up-pipes that the turbos mount on. The spacers are 5"OD x 2.5"L and 3" tapered to 2.5" ID and have a 1.75" port bored at 25deg to add a 60 deg bend pipe to mount the 38mm h20 cooled WGs in paralell to the manifold. ( a picture and drawing will go here). The assys. are short and can easily be ceramic coated and\or exhaust wrapped.

Im not sure if I can re-introduce the WG dumps to the water cooled exhaust or if It is better to dump them directly overboard. I think the adding a fitting to the water jacketed final elbow could be a problem. A third thru transom exhaust port might be best.

Q: Is there value in ceramic coating the inside of the h2o jacketed manifold, spacer and up pipe to retain exhaust heat??