Thread: Planning to build a Marine 383 Stroker

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Well, I built this monster and man it can get the boat out of the hole like never before. The only expectation not met is that it won't rev any higher than the stock 350 ever did (4200). I would have thought that the extra oomph in size would have bought me a bit more top end (all I want 4600-4800 RPM WOT) So I ask my machinist and he says drop a Holley 750 on it. My Q-jet is likely already that size, even if it was a 650 probably would still breathe ok?. I'm talking this thing jumped from 70 to 90 Liters/hour on the fuel meter, so am I under-carbed or should I pay attention to my stock point-based ignition?

Anyone have some ideas where I should start looking or do ya think that's all I might get? I have the same prop as before too.

Originally Posted by Nauti-Escape

Well, I built this monster and man it can get the boat out of the hole like never before. The only expectation not met is that it won't rev any higher than the stock 350 ever did (4200). I would have thought that the extra oomph in size would have bought me a bit more top end (all I want 4600-4800 RPM WOT) So I ask my machinist and he says drop a Holley 750 on it. My Q-jet is likely already that size, even if it was a 650 probably would still breathe ok?. I'm talking this thing jumped from 70 to 90 Liters/hour on the fuel meter, so am I under-carbed or should I pay attention to my stock point-based ignition?

Anyone have some ideas where I should start looking or do ya think that's all I might get? I have the same prop as before too.

No matter if you reprop or not you still have a problem. Especially with the smaller prop, that thing should turn up too high.

1. It jumped from 70 to 90 on the fuel meter....Have you run a fuel pressure test at WOT to see if the pump can keep up with the engine's needs?

2. No matter what, you could use some better ignition. Won't hurt and just might help.

3. One of the things that separates boat engines from car engines is a car uses around 25% of it's rated power to cruise and a boat uses 50-75% of it's rated power to cruise. Therefore, your engine could maybe require a bigger carb to feed the bigger cubes.