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Im rebuilding a 454 merc 7.4 gen5, what are some worthwhile upgrades, cam etc.??

Beemer

New member
Its a non-roller cam all stock engine. I have not driven the boat personally so not sure what it needs. Is the mercruiser cam and 4 barrell rochester adequate? Is the stock cam timing ok? the engine has a broken stock crankshaft-is this a common problem? and if so is it worth putting in a steel crank? It has the peanut port heads. Im not trying to build a race boat but looking for any easy upgrades while the engine is all apart. I dont know much about these beasts so any help would be apreceated. Please let me know whats a good bang for the buck. thanx
 
dont see how a crank can snap - stock cranks are usually more than enough for stock applications.. id upload some pics of where the crank broke, mains and big ends too -

something must have failed, oil pressure or something caused that surely - or sth else
 
Freak happening, like a valve dropping in my daughter's fairly new Subaru.

Jeff

PS: Subaru replaced the motor for no cost.
 
I jjust learned that the crank was a Scat brand automotive crank that was installed in a fairly recent rebuild,-no wonder. Old owner said he was at low speed in a no-wake zone when it let go. Now onto a new marine crank and how about some mild performance upgrades?????? Anyone??

dont see how a crank can snap - stock cranks are usually more than enough for stock applications.. id upload some pics of where the crank broke, mains and big ends too -

something must have failed, oil pressure or something caused that surely - or sth else
 
There really isn't any significant 'upgrade' that's cost effective...the factory (GM) specs give decent performance in the power band that the engine operates in....I'd say your money would be best spent going thru the blueprint and balance processes at the machine shop....and make sure the machinist doing the work understands its a marine engine...if there's leftover budget, you may want to consider reducing friction in the valvetrain (rollers)....
 
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