From BC Gulf islands. Want to cross the Straight of Georgia with a little more cushion than the local boats have to offer.

What then do you typically get for fuel consumption?

I only want to cruise around 35 MPH.

GPH around 20?

20 Gallons of fuel per hour would give around 270 HP per hour at .45 BSFC.

What kind of power would it take to push these hulls 35 MPH on average?

We had/have (family boat) a 1980 377 Scarab that cruised at 35 knots at 3200 Rpm with twin 370Hp. That was a 38' boat. I'm sure that 30' boat would cruise at 35mph no problem with 330Hp motors. That's not asking that much from that boat. Someone else will have to chime in about small blocks. Small blocks and TRS drives never seemed like a good fit to me. The drives are big and bulky and eat up Hp. They're built to handle a lot of torque, which is exactly what a small block doesn't have.

My 32' Baja has the 330Hp motors in it and cruises around 35, and that is approx. 20GPH of fuel. Gull island is around 25-30 minutes for me each way (1hr round trip), and it costs me around $60 in gas (20 gallons), give or take, depending on conditions.

As for value of a 1977 30' scarab with twin small blocks, I wouldn't pay more than $10,500, and that's if you REALLY like everything else about the boat (hull condition, interior, etc.), and have it surveyed!!!.... It likely needs more than a tuneup and steering cable.

The asking price is $6000.

Gelcoat looks good though does have bottom paint. Upholstery is updated and in good condition.

I have of course checked out the threads on here about the other restorations of Scarab II. Fuel tank may be an issue as well as the transom.

Small blocks can be made to deliver plenty of TQ. Do they have the same power potential as a 454? Not really, but a small block can be punched out to 454 cubes. Not really reliable for the marine application though.

A good 383 w/ alum heads would provide great TQ and be lighter than the big brother. Make up for the extra weight of the TRS. I think though that the SBC with TRS would be a reliable package as stock they will have less TQ and not shock the drives and make them last way longer without major overhaul.

What does a good survey cost?

With smallblocks, if you were to have to do the transom on it, I would switch to bravos in the process. you can make enough selling the TRS stuff to really cut the cost down, small blocks on a 30 should not eat bravos and the bravos should be much more efficient and pick up some speed.

A good survey should cost $200-250ish.

I agree with Phragle... If you do end up doing transom work, spend a little money and get Bravo drives.

$6K seems very reasonable if the boat is in good shape.

My 77 300 has very basic 383s with stock heads .. just changed ignition to cheap HEI set up and Edelbrock performer intake and carb... runs very efficent and unless you need to run better than 45 crusing speed the small blocks work fine and you can save a ton of cash changing everything out...3200rpm crusing at 43/45 is good enough for me. I have less then 6k in mine and have run it for last two yrs without any problem at all... just depends on what you want and how much time and cash you want to put in the project... Do I get the itch every now and then for more speed... yep... just like most everyone else does... just haven't been able to talk myself into it...

I understood that the 300 was the the model before the Scarab II. Then I see the scarab Panther and it looks like the 300.

TRS drives use the Velvet drive to control FWD/REV. I don't think they have a reduction in FWD? Could be wrong. Then if 1:1 and the reduction is in the leg, then there should not be much power lost in the straight through setup. Without the FWD/REV clutch cone on the prop shaft, aren't these stronger?

I have heard it said that they are less efficient hydro dynamically, but maybe a nose cone would fix that?

Either way, these sml blocks still have exhaust coming through the leg. They weren't putting too much TQ through the TRS.

Is the Bravo that much more efficient? Would it really justify the cost going to Bravos? What is a complete Bravo worth used?

If the 300 you are looking at is original like mine, it will most likely have Merctrans II transmission with electronic shifter. The merctrans II wont handle much more than 400hp and 400tq and last but... it is very efficent if you do a couple of things... change the trans cooling line from dumping into exhaust manifold and dump it direct thru the hull. This takes the backpressure off of it and it flows water much more efficently keeping it nice and cool. Change trans fluid to B & M trick shift fluid... The electronic shift mechanisum is garbage and replacement motors do not exist... change shift mechanisum to mechanical using factory conversion bracket and cable.... I will have to look back and find the vendor I bought mine from but I believe the total conversion cost me about 650 but I had the shifter controls for the dash so maybe 1000 and took about 6 hours to change... The TRS outdrives are basically bullet proof... pressure test and reseal if necessary and change fluids to merc HI Performance drive lube ... Yes, they are big and heavy but with small blocks and MercII trans... thay will last forever... If speed is the goal.... this is the wrong boat to start with... Too many things to change to get there....

Part of the problem with the hydro dynamics of the TRS drive is that is just sits too deep in the water. From what I understand you can make up for some of the design shape/hydro dynamics with a nose cone, but that doesn't really help the boat any until 70mph +, and nose cones are supposed to slow the boat down below that speed.

They're just a big, beefy, deep, heavy drive. Also, their use of an external transmission is supposed to eat up some Hp too. The Bravo stuff has lighter rotating parts, an internal transmission, and costs less Hp to spin. I would tend to think that the efficiency (not to mention the ease of getting replacement parts), is well worth the swap if you can afford to make the change.

Also, if you have to do a transom on the boat (I know that was questionable in one of your earlier posts), you already have to do one of the most expensive parts of the swap. It would seem silly to me to go through the hassle of de-rigging the boat and rebuilding the transom, only to put those archaic anchors back in the boat. If you can sell your TRS parts for a reasonable price it should only cost $3-5K to make the swap, and it will be MUCH cheaper and easier to repair any drive problem you may have from then on (not to mention picking up a ton of room in the engine compartment after negating the transmissions).