Good chance it could be a timing issue.
That would be the first thing to check for sure
Need more info!!! Hull type, weight, loader style if any?
X2
I agree.
What do you honestly predict this motor should make for horse power and where is it (peak HP) made (RPM) given the combination you have described and assembled ?
Well Bob, in under a half hour I could top stop the piston verify cam timing and have a TDC mark to set timing from
Was the pump rebuild with the engine rebuild? If it was fairly worn prior to bebuild, tightening up the pump likely countered some of the rpm increase you would have seen with the added HP.
If the engine you built is capable of making an honest 450 HP at 5k then your clearly down on power as you suspect , could be a simple tuning issue ,think you indicated the pistons are dished may be the wrong cam choice for the compression ? do you recall what the compression ratio ended up ? might have missed it but did you degree the cam ? for reference sake a production 460 marine motor in the 70s made around 320 HP , according to your 4500/4600 rpms your currently making around 350 HP (Jacuzzi B will develop much like a Berkeley A)
I think that you are on the right track with the cam being the limiting factor if your timing set-up is correct. I think your cam should be above 600 lift to get more performance, but you should talk to one of the cam guys here on the boards for best recommendations. You might even think about after the cam change, going bigger on the carb.
Bigger??? I would suggest SMALLER, maybe 750 and jet it for correct a/f ratio... You can feed a big dog all day, but that same dog needs to shit, and shitting through log exhaust could create some heavy duty constipation.... There is no way that combination needs that 850 carb....
