1975 mark twain mercruiser 302 ford engine

[jeremy888]

well to start with i have cracked exhaust manifolds and a cracked elbow
unless im wrong they cant be welded because they are cast iron
so i was wondering if i can remove all the exhaust and just install automotive headers on upside down then have the. rest of what i need made..to have it thru hull exhaust
but not sure if that can be done or not
i question if it will be to hot without water running thru the exhaust
i know i have seen thru exhaust kits but they use the excisting manifolds

someone give me some advice or know how if possible thanks

 

[Bt Doctur]

Re: 1975 mark twain mercruiser 302 ford engine

Only if this Mark Twain is a drag race boat with an open engine.Otherwise no, way to much heat would be available to start a fire or seriously melt something.

 

[haulnazz15]

Re: 1975 mark twain mercruiser 302 ford engine

Agreed, you need water-jacketed headers if you are going that route. Even so, don't put through hulls on a MT, it just ruins the classic look. Also, contrary to popular belief, thru-hulls won't give any power increase over running it through the prop like it is now. If you want to save yourself a lot of headaches, buy the center-riser conversion kit from ebasicpower.com. It comes with everything you need to get rid of the "log-style" manifolds which are likely shot by this point if they are originals.