Engine will not reach max RPM

Hello All:

I have a 1981 Southwind with a PCM Ford 351. I recently had water in the engine oil and had new head gaskets installed, heads planed, new exhaust manifolds, new plugs plus other misc new parts. The oil was changed 5 times to clear out the water. The oil looks perfect now. The engine used to max out at around 4400 RPMS. Now it only gets to 3600 RPMs. Timing is 10-11 degrees BTDC at idle, timing, advance is okay, dwell is okay. It sounds great and runs smoothly but won't go past 3600. It has around 450 hrs. The marine mechanic who did the work is a very experienced and I have known him for years. He can't figure it out.

Any thoughts??

What should the compression be? Thanks.

So, same boat, prop, etc. and lost 800 rpm. My first comment would have been to check advance and total timing, sounds like you did that, when you say advance is OK you had a timing light that could read total timing?

If not timing then fuel, might want to get a pressure gauge on the fuel delivery to make sure the pump is putting out enough pressure post rebuild. Also look to see if secondaries are opening fully.

Agree with Mark.

Was also thinking to check that the throttle cable is allowing the carb to open up to full throttle. A lot of stuff on your top end was taken apart and put together. Throttle cable is an easy thing to pinch or potentially to connect wrong.

I can see getting 110 since the engine wasn't rebuilt, but would not expect 110 across the board, more of a range than that. Just guessing but seems unlikely it would be that consistent. How many hours are on the engine? Anyway, I don't think compression is your problem so go ahead with the other suggestions.

samudj01 wrote: ..ended up being the distributor advance. Make sure the plates move freely and that the springs are still good. "

starbox189 wrote: Timing is 10-11 degrees BTDC at idle, timing, advance is okay,

What is the advance your mechanic found or did he just tell you it was "OK"??