X-Rated30

Last year I replaced gen IV 454/425's with new gen VI 454/425's. They don't seem to have quite the bump I wanted, but are definitely adequate. (Have gotten mid 70's gps.)

The new motors are the 454HO crate motors from GM performance. They have hydraulic roller lifters, and compression is 8.75:1. Heads are cast iron rectangular port 118cc.

I am toying with the idea of supercharging them. I don't want to destroy the motors, and I thought a slower turning larger blower might be the way to do it.

I have two questions:
1) should I supercharge these motors at all? If so, what if anything would I need to change inside the motor.

2) what kind of blower/setup would you suggest?

Pure Energy

Are these marine motors? I procharged my Merc. 454 with great results. Reliability is all in the initial set up and how the driver runs the motor.

X-Rated30

They are souped up car motors. It is a fresh water boat, so the main worry was getting torque in the right places. The sheets on them say 500 lbs of torque at 3250 rpms. Can't dissagree with that. The low end is fine -- the top end dies out a little soon for my tastes, though.

Pure Energy

There is more to it than where peak torque and hp are. I am no mechanic but I do know that some of the tolerances and clearances are diff. Marine motors are built to withstand the severe load they have to endure. Auto engines are not built the same. I am sure there are others here that can shed more light on the subject.

KAAMA

iTrader: (1)

Sgrady (OSO board member) has had experience with Pro Chargers in a boat he once owned before. Wolff installed them and got them running well for him. Maybe he will chime in here.

X-Rated30

I'm moving this post to the main board to get a little more input. If you want to respond, please post it there.

THX!

Turbojack

Change the cam shaft. Not a real good one for marine use, so I have been told. Then procharge them! Got buddy on third season with 2 of them & no problems.

cobra marty

Car Craft Aug 2002 just did this, it's a great article.

Found stock GM crate 454HO put out 472HP with stock auto manifolds, and 481HP with headers.
472 HP--stock
481 HP-- +headers
490 HP-- +mighty demon carb
506 HP-- + Edelbrock performer rpm dual plane manifold
508 HP and -30 TQ-- + Edelbrock victor jr. single plane manifold

532HP-- + Crane cam #168761 230/236 degree, .598/.610
plus lifters and springs = $1000.
779HP-- + Vortech SC at 7 pounds boost @ 6100, and 706 TQ @5500 (victor jr manifold), no intercooler, 91 octane gas.

It is a little high in the rpm range and I would love to see this with the stock cam (save $1000) and the Air gap manifold.