flexplate or flywheel

[jdfougeroussse]

I have a 1989 Chaparral Villian III with mercruiser 7.4l i recently blew the engine. (3 pistons gone) i have another 454 engine from another boat that has been balanced and blueprinted. the new engine has a flexplate and the blown engine has a flywheel. is it permissable to bolt the coupler to the flexplate intsead of changing to the heavy flywheel.. also boat has a bravo1
thank you in advance for all the help

 

[mkast]

Re: flexplate or flywheel

What generation are both engines? Year?

 

[jdfougeroussse]

Re: flexplate or flywheel

The Engine That Is Blown With The Flywheel Is A 1989 Mercruiser Big Block 454mag Assuming Gen V. The Engine That Is Going In The Boat With The Flexplate Is A 1972 Rat!! Any Help Would Be Greatly Appreciated

 

[maxxman04]

Re: flexplate or flywheel

no, you cannot use a flexplate. it's only 6 bolts to swap them out, providing both are same generation. with the constant, heavier than normal load on the engine, you need the extra weight of the flywheel to keep it balanced right. the older big block may have a different size hub on the end of the crank, bigger than the newer crank. double check that.

 

[jdfougeroussse]

Re: flexplate or flywheel

Thank You So Much I Was Just Wondering Because The Engine Is Coming From A Jet Drive Boat And Is All Been Balanced But Well Give It A Try Swapping Them Out And Hope The Balance Is Ok...... Tks

 

[diehard]

Re: flexplate or flywheel

use your fly wheel off blown moter the thin flex plate will not hold up to the hp of the big block in a boat .. they all have the same bolt pattern as long as there both internaly balanced with 2 peice rear main seal or both external balanced .i used to crack flex all the time in my truck with a big block....[sorry i can't spell]