scarab motor and drive hunt questions

I just bought a 30ft scarab with no motors drives or trailer. I've got the trailer taken care of and one drvie/motor. The boat had alphas in it i'm pretty sure because the openings match my alpha template. I've bought one parts boat with a 305/alpha gen2 and am looking for another. I've built a few jet boats but i'm new to outdrives so i wanted to buy complete parts boats to help educate myself as i pull them apart. And it seems cheaper than buying one part at a time. My question is, are the engine bell housings the same for all chevys. I plan on buying new drives after i get the boat set up with these. So could i buy a 4.3 or 4 cyl boats to get all the stuff and then when i replace the drives buy new same/proper ratio drives. I know if i stick with 305 or 350 stuff i'll get manifolds wiring harnesses and such things that i will need. But I planned on buying new manifolds and i'm going to use two fresh truck motors that i already have setting in my shop. So is it worth trying to find cheap v8 alfa gen 2 boats when i'm not going to use the motors anyways and is it even possible to use the 4cyl or v6 stuff. Any thoughts and opinions would be greatly appreciated. I know this post was kinda wendy, but i didn't know how to ask it any shorter.

Re: scarab motor and drive hunt questions

Two words...gear ratio!

4cyl, 350 and big block...all use different gear ratios for their different rpm range.

Just my opinion, if you rebuild, it may cost a lot!
Look at re-power marinas, marine mechanic shops, they usually keep the best take offs and re-sell with a warranty.

As far as using the truck motors, marine engines have a different cam, brass/bronze freeze plugs, alloy head gaskets, and marine alternators.

All of which can be changed by someone handy.

Re: scarab motor and drive hunt questions

So is it worth trying to find cheap v8 alfa gen 2 boats when i'm not going to use the motors anyways

Click to expand...

Ayuh,... There's lots of Stuff you won't have to convert your long block motors, to Fully dressed marine motors, besides the Manifolds...

Get another V8...

You still need Induction, Igntion, Electrical, Alternator, Starter, Cooling housings, etc....
Ton$ of Ca$h, by the piece....

Re: scarab motor and drive hunt questions

Two words...gear ratio!


I plan on putting new drives on after i get it all set up and at that point i will order drives with the proper ratio and then sell these drives to help offset the price of new drives. I also planned on getting one counter rotation. That was part of the plan, but my post was so long its hard to catch it all. Sorry.
Ok, so i should keep going the way i was.
Buy another v8 boat. The first parts boat runs good and everything seems to be in good shape and i only gave 1100 for it. I've found another for 2500 but i'm patient and will find one cheaper. I was told that truck cams are close to a boat cam, but i don't have a problem swapping cams while its all still apart. And i'll put brass freeze plugs in them as well. The motor stuff doesn't bug me, im use to it from my boat experienc, i'm plenty ignorant with the drives though. I'm still curios though, are the engine bell housings the same? I've been told the 4.3 is the same just as they are in autos. What about the straight 6 and 4cyl motors/bell housings?

Oh and thanks for your input. I really appreciate it.

Re: scarab motor and drive hunt questions

Ayuh,... The cams will be Fine, so longs they ain't worn out...

The boat you bought probably has a 2bbl. carb...
You'll no doubt want 4bbl.s when yer done....

All Chevy bellhousing bolt patterns interchange, since around 1955 or so...

Re: scarab motor and drive hunt questions

Thank you for your time.

I was planning on going with alluminum intakes and new distribs and i have four barrel carbs already. So if i find a really cheap four cylander boat it might not be such a bad idea just to buy it for the coupler engine bell housing, gimble housing pump trim cylander and a drive/trailer to resale?

Re: scarab motor and drive hunt questions

Ayuh,... Distributers, 'n Carbs, Must be Marine rated....

Aluminum intakes are Ok in freshwater, butwill turn to dust in the Salt...

I'm tellin' ya,... Find another V8... We ain't even got to the Plumbin' yet...

Re: scarab motor and drive hunt questions

Man, you just missed the boat, two complete brovo drives with everything, inner and outer transem plates and most hardware just sold on ebay about 4pm for just over $2000.00. If I was doing the swap I would go brovo's all the way. I ran with my brothers 30ft scarab which had trs drives, your going to be pushing a lot of weight. I know you will never crack that throttle, that's what we said. I now have a 26 nova ll with twin 350's. The boat dry weighs 5500lbs and a 30ft scarab will be close to 8000lbs. I still remember the tears when we broke something. those big blocks will tear up those alphas with the weight you are pushing, This time of year there are some good deals on ebay. Good luck Buz

Re: scarab motor and drive hunt questions

thanks bondo and buz

Ok, sometimes i'm just hard headed. I'll keep looking for another v8 boat. Actually its not hard headed, i'm just finding a lot of 4 and v6 stuff. But it would be a lot easier having everything right there.
About going with bravos. I would love to go with bravos just can't afford it. I hope that if i stick with small blocks and keep them mild to stock and stay out of the throttle maybe i'll be ok. Thats another reason i was wanting gen2 and new so i can get that three year no fault warrenty. I still have my eye out for some bravos. everything i've found that i could afford is just too far away. can't afford the time to go get it. Am i stupid or just wasting my time putting alfas in this boat? To be honest, i was kinda thinking keep it as reasonable as possible and sell it this summer and buy another project next summer. i haven't spent a whole lot and do all the work myself and so i should make a little profit plus be able to put what i've put in this boat into a newer faster one next winter. thats if can keep from falling in love with this one. thanks guys

Re: scarab motor and drive hunt questions

Truck engins are great if you can do the work yourself. Change the head gaskets and the freeze plugs and you'll be fine. I redid 2 350 4 blt mains all parts and machine work for 2500 each. I did the labor of the r&r and the motor rebuilds. Changed all the tins to alum. flat top pistons, marine cams. GLM manifolds for both motors and have about 290hp insted of 260 for the cost of reman 260s with that rot friendly oil pan, valve covers and timing cover. And I have Alph gen 1 on a 9000lb Tiara.
I have over 300 hours and still running stong and I run salt all the time just flush them really good when you get home

Re: scarab motor and drive hunt questions

I have a 30 ft. scarab with the big engs. removed, and installed 4.3 vortech engs. They have flat top pistons and 202 valves and a summit cam. Runs a little over 50 mph. Good on gas, and very little maintenance. Must use cast intakes. Hope this makes your choice easier.

Re: scarab motor and drive hunt questions

thanks everyone for all the info and advice. my plan as it stands for now is to get another parts boat like i have now and use the stuff off the 305s on my 350s with the alphas and if i can swing it put new alphas on it. I've found several single engine bravos that are almost in my price range so if i just love this boat and want to go faster then i will start hunting some bravo setups and part out all the pieces i don't need. I do this with vehicles and it works well. buy a truck with a 350 put in a 305 and put a decent paint job on it and resale and actually make a little. I do custom paint on the side. A cool paint job will sell a truck in a hurry most of the time. Thanks again everyone.

Re: scarab motor and drive hunt questions

Ok, i have another question. I've heard arguments both ways so maybe someone can explain this to me. Is it stronger to run a drive with 1.47 ratio and smaller prop or something like a 1.84 ratio with a larger prop. I was told by the person i trust the most that the 1.84 will be the strongest way to go. running 1.84 is stronger in the upper but puts more stress on your lower. And his point was how many bad lowers compared to uppers do you see. And in my looking i haven't seen too many bad lowers but a lot of bad uppers. What do you guys think? That makes since but he also said a smaller prop is less effeciant and will (if you will) slip more. In my street experiance slip keeps you from breaking things. You put some really soft slicks on the back, you'll find the week link really fast.

Re: scarab motor and drive hunt questions

Ayuh,... You're building 350s, Right,..??
So, go with the 1.5:1 outdrives...

Goin' with the 1.84:1 drives will just mean you'll need Custom props, which are ungodly Expensive...

Your friend is Full of it...
Lower units die from being Wacked on realestate...
Upperunits usually Die from a lack of oil....
When there's a seal Problem, the upper is the 1st to run Dry, 'n Die, takin' the lower with it...

Re: scarab motor and drive hunt questions

Bond-o said:

Ayuh,... You're building 350s, Right,..??
So, go with the 1.5:1 outdrives...

Goin' with the 1.84:1 drives will just mean you'll need Custom props, which are ungodly Expensive...

Your friend is Full of it...
Lower units die from being Wacked on realestate...
Upperunits usually Die from a lack of oil....
When there's a seal Problem, the upper is the 1st to run Dry, 'n Die, takin' the lower with it...

Click to expand...

oh ok, that makes since. He has a buddy here that builds or rebuilds props for him. Hes put like 16 something props on his boat to get it just right. But he's done a lot of work to his boat. he has changed the angle and location of his drive. My ignorance probably makes hims sound stupid but he isn't. I'm knew and learning sorry.

Yea, i'm going with 350's and i have a 1.47 ratio already that has a nice stainless prop on it. But i'll have a better chance getting a stock prop to fit my boat with the 1.47 ratio? Makes since.

Oh, and yea you are are right. I have seen a lot of bad lowers because they were used as underwater plows. And a lot bad drives that went dry. Thanks for all of you help.

If you have time, what is the difference between a marine distributer and carb verse auto?

Re: scarab motor and drive hunt questions

If you have time, what is the difference between a marine distributer and carb verse auto?

Click to expand...

Ayuh,.... Igntion Protection...

Marine electronics(dist. alt. starters. etc) are Sparkproofed by venting through screens...
Carbs are designed to leak within themselves, Not onto the motor...

Re: scarab motor and drive hunt questions

ok, thanks.

Re: scarab motor and drive hunt questions

ih4by4 said:

Ok, i have another question. I've heard arguments both ways so maybe someone can explain this to me. Is it stronger to run a drive with 1.47 ratio and smaller prop or something like a 1.84 ratio with a larger prop. I was told by the person i trust the most that the 1.84 will be the strongest way to go. running 1.84 is stronger in the upper but puts more stress on your lower. And his point was how many bad lowers compared to uppers do you see. And in my looking i haven't seen too many bad lowers but a lot of bad uppers. What do you guys think? That makes since but he also said a smaller prop is less effeciant and will (if you will) slip more. In my street experiance slip keeps you from breaking things. You put some really soft slicks on the back, you'll find the week link really fast.

Click to expand...

flip the 1.84 over to 19 to 17 . this is 1.33 to 1 same strength as 1.84 but much faster. strongest gear set on the market for alpha drives. have never broke one yet. can be ordered from m/c and well worth the money

Re: scarab motor and drive hunt questions

rjedney said:

flip the 1.84 over to 19 to 17 . this is 1.33 to 1 same strength as 1.84 but much faster. strongest gear set on the market for alpha drives. have never broke one yet. can be ordered from m/c and well worth the money

Click to expand...

ok, say that again. you kinda lost me a little. I'm new to this so i'm pretty ignorant. Are you saying swap the upper gear set to the same as a 1.47 and leave it with lower ratio 1.84 lower unit?

Re: scarab motor and drive hunt questions

can be ordered from m/c

Click to expand...

Ayuh,... Got a part # on those gears,..??

I find 'em for mod.1s, 'n Alpha 1s, at $600. a set.... Nothin' for GenIIs...

Using the 1.50:1/ 1,47:1 gears will keep this well within the normal pitch range of more common props...

Donno's they're much Stronnger either,...
The BBC/ Alphas ran 'em, 'n they Split the top gears quite regularly...