ctadams21

Do the 365hp 454s have forged pistons? Roller cam?

Thanks,

Clayton

Pat McPherson

Forged pistons yes.
Roller cam in Gen VI engines, 1996 and newer.

KAAMA

iTrader: (1)

The Merc 454cid/365hp engine came with the very crude stamped steel rocker arms, but it does have all forged parts---crank, 7/16" rods, and pistons including a 4-bolt main block, and rectangle port heads. I don't know up to what year that Merc produced the 454cid/365hp engine, but when it first came out in the mid to late 80's it came with a flat tappet hydraulic camshaft.

ctadams21

Thanks guys. Just wondering if these engines were a good candidate for 525sc conversion. Sounds like they would be o.k. with a cam change and maybe some roller rocker arms, and the blowers of course.

Later,

Clayton

Pat McPherson

A Merc 525SC is/was basically the 454Mag with a supercharger.
Dished pistons, Crane cam, and roller rockers are among the differences.

Gary Anderson

Might be worth a set of low compression pistons if you're doing a rebuild.
The 525SC CR is only 7.5:1.

CMG

had a set in old boat, good motors

KAAMA

iTrader: (1)

Clay, I would say "yes" to your question. On the reliability side, I would at least add some roller rocker arms, ARP rod bolts, hydraulic roller cam/morel lifters, and a good set of pistons designed for supercharging---heck, the pistons you have may even be okay to use for supercharging, but if you want to be top notch I would consider new pistons. I would also and have the engine(s) balanced.

Just make sure you have a precision machine shop who is known well for their machine work and good reputation----a shop that is very familiar with clearances needed to make an engine survive in the marine performance world.

"rmbuilder" (Bob Madara)is a good man to contact for valve train components, and very helpful when it comes to cam selection. Have fun with your project.

ctadams21

Thanks guys!

Big Block Billy

365 motor has Trw L2399 forged pistons. I believe .095 dome. BBB