Did not change the valve size. Did go to an upgrade material though - inconel or titanium I think. My 330's were 4 bolt mains and were strong motors. I have 2 - 525efi's in my current boat and lost both of them at 112 hours. I miss the old iron and I could work on those motors. Cam sensors, injectors, multiple coils, ... - it all sucks now a days! Tommy

full port 240 to 250 bowl port around 225 increase in valve size wasnt worth the money.

Thanks for your response Tommy. I think it is pretty impressive that you made 424hp and 509 ft/lbs of torque on the dyno without using larger valves. It would still be interesting to know if you still had the peanut port heads bowl/pocket ported with the stock valve size with the dyno figures you obtained? Thanks again

Turbo, thanks for your valueble input. Much appreciated!

I had stock heads. The engine shop did some mild porting of the heads only to match the intake. I don't think there was any bowl porting of valves. Both engines dynoed very close to same numbers. The reputable machine shop was impressed with these numbers also based on the peanut port heads. Everything that was done worked well together without any 1 items overpowering the other. I did have better performance with the slightly less air flowing Edlebrock RPM manifold in lieu of the RPM Performer though. I ran the Performer after the salt ate the non-coated RPM intake thinking it would be an upgrade.

Get some 702 style old 60's Closed chamber large oval heads, change cam, and rejet carb. Also add hi octane gas. This will wake up the motor.

If you don't want to change cams, Just put some 1.8 roller rockers on it and it is like a bigger cam. The rockers also give it a faster ramp on the cam so it works closer to a hyd. roller cam only alot less work!! You will have to put in new studs, and aftermarket valve covers, But it is well worth it . I changed just rockers on twins and gained 300 rpms a motor.

Thats a great idea , easy upgrades , thanks