So I'm kicking around the idea of doing some motor work this winter. Either a valve job with a cam upgrade or a full rebuild.
Here's what I have. 1981 Eliminator V-drive cruiser. Engine is a Harman Marine 405hp 454 that has never had the heads off to my knowledge. It has rectangle port heads, RPM air gap manifold, MSD dist with 6-AL box. I believe but am not sure that it is a 4 bolt block with a forged crank and rods. Also I believe the cam is an Isky marine cam.
I currently run 60mph at 5000 rpm and thats all she goes. At 5000 rpm I start to hear noises that make me feel nervous about my valve train. I have broke rockers and pushrods when I first bought the boat but I believe the valves were not adjusted correctly. It has now seen 3 summers of abuse with no real problems. But I've got to think the valve springs are tired and it's ready for at least a valve job after 27 years.
Important fact: I am on a budget.
What I hope to accompish is a little more HP maybe 450 and around 5500 rpm wide open.
I do want to go with a hydraulic roller cam and my first question is looking for cam recomendations. I was looking at the Comp Cams Extreme Marine kit with springs, lifters, timing chain etc. There is just so many cams to choose from.
Also I was looking around on Ebay and I noticed few choices in roller rockers and lifters at good prices. Are steel roller rockers OK for my application. Should never see 6000 rpm.
Last time I checked my compression I was 145 to 155 in all cylinders. Squirting oil in the cylinders did not raise the compression at all. I am going to check it again before digging in but if it's the same I'm considering pulling the heads and seeing what the cylinders look like and how much ridge there is. If it looks good can I get away with just a valve job? Or am I asking for trouble not doing the whole motor.
Interested in all opinions.