MILD THUNDER

To be honest, from a power producing standpoint, I don't think the new builds are that much better than the old engines. Quality wise, you now have some better components. Better blocks, cranks, rods, pistons, carbs, heads, lifters etc etc.

Guys don't wanna believe it, but those old procomp heads gellner prepped, probably flowed pretty darn well. Sure they are chinese castings that had issues, but they were decent flowing heads, and I'm sure after Dean went thru them, he improved them flow wise a bit. From a power standpoint, I don't believe switching to the AFR's and a new cam, was gonna transform it from mild to wild.

The old builds made 600ish HP if I recall, around 5300RPM, and that was prior to dean doing some work on the heads. The new builds, while capable of probably 650-675hp, my guess is that would be around 6000RPM. At 5300RPM, you're probably making around the same power, as the old engines. To see a gain performance wise, you're probably gonna have to step down in pitch, to get the R's up. That will maybe net you a slight increase in top speed, and a decrease in cruise speed at 3500-4000RPM.

I wouldn't beat yourself up about it. The goal was solid engines that stay together. I'm sure you'll find a little more speed in it with some more tuning and prop work, etc. The mistress is a tank of a boat, and to get mph it takes alot of power. Many times on oso we debate things like a couple degrees of cam duration, .030 worth of lift, half point of compression, and so on, as if its the end all be all. But in the real world, many times, that little stuff, isn't worth chit on the speedo.

Next summer, bolt some 8-71's on those things

Full Force

I was just on the phone with my buddy Bill, hes local engine builder and he said the exact same thing, that they are a hair better with really nice parts, the old engines were maxed out and on the edge, Bill told me this morning.... I lost some CI, heads are very close, same intakes, and mainly just a cam change.... not gonna gain 75-100 hp that easy... unless I put a 21P prop and wing them to 6000 to see the hp then cruise at 38 mph f that.... goal was to use props I had....

Full Force

That's my point on a dyno, I dot feel there is any issue at all with engines, they can make whatever on dyno but in the water is what I care about.... and this boat is HEAVY.... I think I just expected too much from this build.... she passed endurance test that's for sure... 50 gallons I bet last night at WOT

excalibur82

do you have nose cones? I know your not in the 80's but did it on a trs boat that did 70 ish and it picked up 1-2 no BS. What direction are the props spinning?

Full Force

Has nose ones, spinning out... I spun in one weekend last year didn't gain anything ... But a worse riding boat lok

vintage chromoly

How fast did you expect it to run Tim?

Full Force

I am confident these engine would make the 675 or so at 5800-6000 rpm but I was hoping to use existing prop to see it I don't wanna put on 21p to do it

Full Force

I was expecting to be anything faster then before.... Not less....

donzi matt

Try taking vacuum readings at WOT, that will rule out a restriction in airflow.

EDIT: Could you play with your cam timing to bring your torque curve down a little? Might help you get a little more out of it without breaking the bank.

Full Force

Yea I kinda don't see that at this point, even if there was there is nothing I can do to get more... I ran with hatch open too once just to see but no change...

I really think it's a powerband issue and what mild thunder posted, 2 local buddy's agree with that also