all great points.... i like the little mousies and i have always been able to make a sbc hold its own in the land of bbc. not that cars and boats need the same type of power, but the last sbc i built was 436ci in a 3000lb chevyII and went 5.89@121mph on a 1.32 60ft 1/8 mile on 9 inch tires and upset near all bbc it faced.

5250 rpms is the magic# in most combustion engines. this is where the hp/tq cross. the surface drives cavitate untill on plane, so its not like i need a ton of torque to get it moving just enough to get it to 5250 with the props i have. hp sales motors but torque wins races!

5 mph is not worth a swap to me and if i cant get more then 5 mph out of building motors i need to trade this thing for another V drive. lol....

Duece, lets see some pics?? And welcome to the 300 club

It may be a turd, but at least its a floater! I say buy some Hp 500's and have a blast!

I think you missed the point on the 5mph reference. Equal Hp big blocks produce 5mph more over a similarly powered small block. And on top of that, it's much easier to get 500+ lower rpm reliable Hp out of that big block.

I agree with you that in cars their really isn't all that much of a difference between a BB and a SB, unless you're trying to make max HP (more than 800 for sure). When your car weighs 3000 lbs. or less and your motor is in the front of the vehicle and the weight needs to be distributed to the back that extra 160lbs. makes a pretty big difference, esp. given the modest Hp gain of having a BB. That said, when you're driving something that already has the weight where its supposed to be (near the drive train) and that something weighs nearly 10,000lbs. that extra 160lbs. means very little.

BBC's will make way more torque. Pull the SBC and save for the next owner if you are worried about resale. Not sure if this is an issue in that boat but if you decide to look into the BBC make sure the spacing between them is wide enough. No mistake for displacement in BB's!

As far as motors go, and since you stated yor worried about resale value... you do understand that no matter what route you take, you WILL spend more than the completed boat is worth to get it to go over 60???????

Stop worring about Re-sale...You bought a 80's scarab. Do what ever you want to it-your stuck with it now

Ha... Both of the last two posts are very true, but it all depends on how you look at it.

Everyone on here knows that boats that are actually intended for use are not great investments. Hell, even project boats are not great investments. Recently (2-3 days ago) there was an absolutely beautiful 1985 Scarab III for sale on Ebay. The poor guy had done a $25K pain job, $25K in motors, and had the interior totally re-done. The boat was, for all essential purposes, brand new. He said that he had over $100K into the boat, and it looked like it was true. After all that work the auction ended with a final bid price of about $29K, and really, that's probably about what the boat is worth.

That said, there are sensible upgrades that you can do to a boat that won't cause you to lose your azz. If you spend $3-5k on updating your motors you're not going to see $3-5k back, but if you run the boat for 2-3 years you'll get the majority of the use and enjoyment out of that $3-5K + you should increase the value of the boat $2-3K. However, if you go gangbusters and try to make the boat do more than 60-65mph, you're going to spend a ton of coin and never get more than a $2-3K bump in resale value.

Just for what it's worth, I have stock 330hp BB with exhaust and I see just over the 60mph mark in my 1980 300. Granted thats low on fuel, trimed out and ringing those BB out at 5k rpm. As heavy as these boats are I'm a little shocked they ever put SBC in them.

What kind of exhaust is on those SBC's? I think you guys are ALL missing the most important factor.

If those engines that he has in that boat have stock exhaust, ther is no power to be made there.

If he wants 400+ HP and a cam swap, he will need a good exhaust. THat costs more than a good pair of 330 or 420 mercs.

That is a cool boat, but you really need to think clrealy about what you are going to do.

Good Luck.

Jeff