Here's the dyno run I did on the 383 with a Whipple and 800 Holley. This was at a little over 5 psi boost. It has a Crane 109831 hydraulic roller and vortec heads. This is running in complete marine trim with stainless marine manifolds running wet.

Ahhh, so it's a new MPI. Dang - I don't like that intake much. I do like the cast iron one that's typically found on the 6.2MPI's though. Great with a carb on top of it. Ooops - just spilled a scret. LOL.

Those are impressive #'s !!! That thing was still building power, which makes me ask, why is the torque peak more than 2000rpm below the HP peak? With that much torque, maybe it really wouldn't matter in a smaller boat.
The cam in your motor has 18 and 16 degrees(respectively) more duration than Blowncrown's cam. In fact that 196/206 cam is what GM uses in their 383 Vortec headed crate motor which HP. peaks @4500rpm. It looks to me like he needs about 10 degrees more duration.

[QUOTE=LMAC]Those are impressive #'s !!! That thing was still building power, which makes me ask, why is the torque peak more than 2000rpm below the HP peak?


Yeh, I wondered the same thing. My assumption is that the SC just builds so much low end torque that it shoots that whole 1200 rpm peak torque to peak hp theory out the window. I was tempted to run it on up to 6000 to see what it would do, but I don't plan on turning more than 5600 so anything above that doesn't matter anyway.

Blowncrown is running a procharger so it won't have the low end torque that the Whipple does, but probably surpass it at higher RPM.

The intake on my motor looks like a 4 barrel intake with the throttle body where the carb should be and injectors in the runners.

Oh, good. All this time I thought you had the later model intake. That can make a lot more power. Guess you just need a better cam.

Schweet !!!!

The dude's got the good intake !!!!

Let's cam this beatch up !!!!

Joking - kind of - do what you want. It's pretty stout as it is.

Ok lets put a cam in it! Which one? Like you Bob I don't want to spin it past 5600 or so. Or just fast enough to get me past you know who.

I'm kinda partial to the one I used in these 383's. It's a Crane 109831. I erroneously posted earlier that I had the 821 cam in these engines. If memory serves me right it's .509/.528 lift and 222/230 @ .050 duration with a 112 LSA. That's about as big as I would go. It hasn't killed my 02 sensor idling on the dyno, so I don't think it will revert water badly, although I do have Stainless Marine exhaust on it. The 109821 is a little milder and may be a better choice. I've had one of those running in a Whippled 6.2 for 3 years now. The 6 .2 came stock with the 104224 cam.

Bob, I noticed on the dyno sheet the A/F ratio is down in the 11.2's. Should I have mine running that rich?