Where Can I Find Info on Merc Engine Internals?
 

As I look at used boats, we have the 454 Mag, 502 Mag, HP 500, and HP 525, but the information on what parts were actually used in building these engines is hard to find. For instance:

Crank, Rods, Pistons - forged or cast?
Intake Ports - retangular or oval?
Exhaust Ports - rectangular or D-shaped?
Piston pins - pressed or floating?
Intake and Exhaust valve sizes?

Chevy made a lot of versions of the big blocks, some a lot better than others for performance mods.

Thanks,

Michael

All the engines you listed have 4 bolt mains, forged cranks, forged pistons and forged rods. All GM parts.

454mag, 502mag and HP500 all have GM rect port heads.
454mag and 502mag have 2.19/1.88 valves
HP500 has 2.25/.1.88 valves

525efi uses Edlebrock aluminum heads. Not sure of valve sizes, probably 2.25/1.88's

Piston Pins---I think are pressed in on all, but not sure.

best kept secret!

I believe the HP500EFI has forged aftermarket rotating assemblies. Have been told Lunati crank, JE pistons, and Manley h-beam rods, along with the Crane roller cam and rocker components.

Larry

62 Bel-Air 409

260 Eagle XP HP500EFI

2002 Corvette M6 Corvette

The big block Dennis Moore book has lots of this info in it.