Is This Cam To Big?
 

I rebuilt my 330HP last year. Tried for 9:1 compression. Added a fresh set of 781 large oval port heads, Edlebrock carb and intake. Cam listed below. IMCO Power Flow Exhaust. Gained absolutely no additional RPM. I checked compression before I pulled the engine last fall, 150 PSI on all cylinders. That did not sound very high to me so I thought about the cam. I talked to Dennis Moore and he said that should be a good choice. In his book he states this is the largest cam that should be used in a marine engine. What gives? To big for my little combo?
COMP 11-242-3
Gross lift 515 520
Duration at .050 224intake 230 exhaust
Lobe Separation 110
I degreed cam ia at 106 center line like suggested.
New valve springs with valve job

Re: Is This Cam To Big?
 

Any comments from any of you cam experts :D

Re: Is This Cam To Big?
 

Needs more cam and more cylinder head :( The changes you made are not much above stock, truly need to check AFR as it could be going rich on the top end reducing power too.

Re: Is This Cam To Big?
 

What rpm did it used to run? What kind of boat is it in? It should be a torque engine but it will be all over by 5000 rpm.

Re: Is This Cam To Big?
 

It ran 4900 to 5000 RPM. Boat is a 22' Pachanga

Re: Is This Cam To Big?
 

You can always try more propellor and see if it'll pull it. I would expect it to be a little faster.

Re: Is This Cam To Big?
 

I would not have picked that cam soley for the lobe seperation. 110* is too tight for wet exhausts. Too much of a chance of reversion. 150 psi is a good compression number for that combo. I am sure you are losing compression with the small lobe seperation.