Has anyone ever used a port and polished intake manifold on this motor and is it worth the expense. If I decide to do it can anyone recommend a carb upgrade also
4.3 maybe 200 hp available in stock config.
Best you can do is "gasket match" everything.That is lightly glue a gasket in place , grind away any overlapping cast iron on the intake, carb base, heads (intake and exaust side), exaust manifolds.
Polishing the intake Manifold really don't do much good... Same for the heads, really...
The Real choke point on boat motors,+ Chevys in general is the Exhaust side of the equation....
I just pulled my carb off my 2004 4.3 and was surprised to see the same crappy black paint on the inside of the intake manifold as the outside, but with a much rougher finish. It made me wonder the same thing? It sure seems like the gas flow would be smoother and less obstructed.
The course pitted surface keeps the gas in suspension, instead of falling out+ clinging to the surfaces...
When porting Heads,...
The Intake side is always left a rather course finish...Hogged out for shape,+ flow,...
But left a tad Rough...
The Exhaust might be Polished abit....
Chevy's are choked up on the Exhaust side,+ Boat Manifolds(exhaust) choke 'em up even more...
