SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: USCvictory on July 11, 2012, 09:17:39 AM
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I have a 350 in my boat now. Not sure how old it is but I am assuming it hasn't ever been rebuilt. I feel like the SB needs to be rapped a lil high to be in a cruising band. We had a built BBF that would cruise at 3000-3500 no problem. This seems like it needs to be at 3800-4000. I thought about a 383 stroker or just going to a 454/460 set up. Has anybody made the switch or should the SB be fine with a freshen up and some bolt ons? It's 19' Daytona with a berk JC-A.
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I will probably be in the minority here but the cost of new exhaust, mounts, carb etc. will go a long way towards building a new mouse. When I was a teen our mostly stock 400 SBC had enough grunt to pull up 5 skiers at once. I don't think it ever turned 5000 rpms and it sipped gas. Some pretty crazy HP levels are pretty ez to obtain with mouse motors nowadays.
But I'm sure the rat moto lovers will feel differently.
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Great point. That money can be applied to more power. Pacific Performance can get me a fully forged 383 short block for $2300. That seems reasonable. want to get my plan in order for the off season.
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I would agree. I would probably build the engine as a 383" stroker and freshen up the pump.
I would take an educated guess you are likely to find a B impeller in that pump, regardless of what the tag says, if it was set up as a SBC to begin with. That and/or the weight of the boat may account for the RPM differential you are talking about. ;)
Now, if you are convinced of going to a BB, going to a 454 would be far easier than a 460, however. Your driveline and bellhousing/rear plate (depending on 3 pt or 4 pt mounts) can be reused, as well as possibly the flywheel. you would have to replace and relocate the front plate or side mounts (again, depending on 3 pt or 4 pt mounts) and then play around with crankshaft centerlines and driveline angles.
Nordie changed his old boat over from 460 to 454 awhile back. Don't think he wants any part of doing THAT again. :screwy:
Ray
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I have a 350 in my boat now. Not sure how old it is but I am assuming it hasn't ever been rebuilt. I feel like the SB needs to be rapped a lil high to be in a cruising band. We had a built BBF that would cruise at 3000-3500 no problem. This seems like it needs to be at 3800-4000. I thought about a 383 stroker or just going to a 454/460 set up. Has anybody made the switch or should the SB be fine with a freshen up and some bolt ons? It's 19' Daytona with a berk JC-A.
If the rpm seems high for the speed, maybe you should look at the jet pump first, since a different engine won't change that? If you are not planning on using your block, I would give some serious thought to building a 400. You could build one with a stock crank, forged pistons and longer rods (the stock 400 rods are undesirably short)
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Maybe I'll start with the pump and keep the SB. Then like you said I will most likely find a B inside. The boat did come with a SB from Daytona in 85.
I thought about the 400 deal but the blocks are hard to come by from what I hear. Though I haven't looked around much either so I could be talking out of my ass. It sounds like everyone knows and believes building the SB is the better choice.
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Keep the sbc, and look in to the pump. a fresh pump might just surprise you.
A mild sbc will turn an "A" impeller ~4600 rpm, cruise at 3500 all day long, my saguaro will stay on plane 28-2900 r's. (kids' tubing)
For the money, go 400 (406) over a 383, and go w/ long rods, 5.7"s or 6.0"s
That looks like a fairly large float, so the biggest impeller, "A" or "AA" would get a better hole shot over a "B".
Thats all I got
Daniel