Thanks for the replies... Guess I should have been a little more clear. This engine has behaved this way since the first time it was started. I did swap carbs and blowers before I tore it back down. Since then I have swaped ignition modules and no change. Timing is all in (30*) at around 2800. I will check if it is falling off. AFR's abiet rich, are around 10.5 at 3000 running 98's and 6.5pv's. all the way around. As far as making boost - the guage is moving as I push through 3000 but there is no additional power. It actually seems the power falls off. I will go back to timing and fuel and report back. Thanks!

Sounds stupid but...check your blower belt and make sure its not slipping.

I`m sure you`ve checked the plugs... my story was when i was running rich and had a few long idles on the boat, I was making full boost but both motors were turds and weren`t making any power, they hit a wall and didn`t go over 4000rpms..; changed plugs power came back, turned out the plugs fouled out

i have a few questions were cams degree checked,what is the compression ratio,do you have powervalves in the secondarys.it sounds like it might be so rich it cant burn the fuel,also you need more ignition timing.

Yes
Around 8.5
Yes - Carbs were done by Nickerson originally but had 90's and 6.5's all around. I installed 98's before I installed the O2 bungs because the plugs appeared to be too lean. I agree now it is too rich, but the SB engine is running just fine.
Timing - I think this is more than likely the issue. Why do you think it needs more than 30* total?
Thanks!

If the intake is making boost pressure, it sounds like the Intake valves aren't opening and you are developing boost pressure quickly. If they aren't opening the pressure has no where to go?

Put a fuel PSI gauge on it and make sure the FUEL PSI isnt dropping. If fuel PSI is good, and timing is showing up at 30* on the balancer, I'd look at secondary ignition, and or carb. Your boost is going up so the air is there.

I'd look at plugs, wires, cap, rotor, and coil if fuel psi is good.

I have to agree with you. cigrocket
What is your cam firing order and how did you adjust the valves?
If you have swapped all components and checked timing advance, something is not sounding correct. Have you done any type of cylinder leak down, besides a compression test?

The cam is a 2-3 4-7 swap. Adjusted the valves using EOIC plus 1/2 turn. Did a leakdown before I tore it apart the first time. Have not done one since.

Why, did you tear it apart, the first time after rebuild?