CROWN MAN

On a 1999 454 mpi with 200 hrs. What should the compression be?
How many HRS. should it be good for, on average? More than a 1000 or less?

Dave M

I think your compression should be around 150 psi. My 454 Mag puked after about 550 hours. Keep an eye on your riser/manifold gaskets. That's what killed mine. I ran in salt a lot and ran hard.

articfriends

iTrader: (1)

150-160 psi

Edward R. Cozzi

Consistent numbers among cylinders is important too.
Don't be alarmed to find 140s.

CROWN MAN

Should the motor be at temp. when checking?

Griff

Yes, and throttle at wide open.

CROWN MAN

So the motor at temp then W-O-T then check?
I`ve never heard about the throttle. what does it do?

Griff

If the throttle's not open, air can't get in. If air can't get in, it can't get into the cyliders to compress.