Alpha on 383 & some questions

[Scarab Fast]

I am new to the forum and not a good speller at that so bare with me. The boats I read about on the forum and in Hot Boat magazine are not all that common here in North GA on lake Lanier. I have some info that some may be interested in as well as looking for some pointers or info myself. Many people asking about the power a alpha drive can handle has also been a concern of mine as well. Keep in mind there is a 1 series and a Generation 2 series that has larger gears, heavier duty and will hold up to more power than the older 1 series that was used on some of the big blocks in the 80's. The Gen. 2 came out in the mid 90's (92-94, I think). The way to tell if you have a Gen 2 is that it has 2 nuts and bolts on each side that holds the bottom half to the top half, Where a 1 series has studs threaded into the top and bottom and you just use nuts to hold the two together. A gen 2 should hold up to 400 or so hp and about 5500 rpms as lonk as you dont hammer it out of the hole alot or get air and come back under a load under full power. Now here is the reason for my research on this topic. I purchased a 22' scarab about a year ago with a froze and busted 350 magnum with alpha gen 2 drive. The motor I built for my new toy is a 383. I started with a used 350 roller block, scat 400 forged crank, eagle H-beam forged rods, forged pistons, new vortech heads, new cam, billet roller rockers, holley 750hp double pumper carb, and imco risers on stock ported manifolds.The motor is 452 hp and 503 ft/lbs torque. This will be a full test for this drive so I will keep you informed if or when it comes apart. I fired this beast off Monday for the first time and it would make your hair stand up. Took it off the trailer for the first time Wednesday for its first run a ran perfect, stayed below 3000rpms for break in. Thursday took it out for the second time, now this is my question for some carb experts, the boat was running really rough like it was flooding out or running really rich, gas in the exhaust. why one day perfect and the next like this on brand new carb? Also any suggestions on props diameter and pitch? Sorry post was so long. Thanks for any help

[DUCKY]

Look down the carb and see where the fuel is coming from. If it's coming from the boosters, you could have a stuck needle/seat, it you can't see where the fuel is coming from, it's probably a blown power valve and it coming in throught the vacuum port in the base plate.
Good Luck!

[Havasu Hangin']

Man, that motor is almost identical to mine...
As for the carb, I am running a Holley 750 (vacum secondaries) which was set up by a local carb shop.
- "J" Tubes were replaced by a cross tube
- Plates were cross drilled
- 800 CFM conversion
- 75/86 jets
- 6.5 powervalve
- .033" nozzle
- seconday spring is purple .063"
It runs very hard with this setup...the "out of the box" Holley was giving my builder fits...

[Scarab Fast]

Havasu Hangin,
What kind of rpms are you turning, prop size and speeds are you getting. I am in the begenning stage of working out the bugs and tunning it in. any help is really appreciated.

[Havasu Hangin']

Scarab Fast:
Havasu Hangin,
What kind of rpms are you turning, prop size and speeds are you getting. I am in the begenning stage of working out the bugs and tunning it in. any help is really appreciated.Keep in mind that my boat is alot older, a little bigger (23'), and probably alot heavier...
With my timing at a total of 36 degrees, I was able to spin a Hill 23" Turbo 3-blade to 5,200 RPMs. I would say you could do at least that..
What kind of gas are you running? Where is your total timing at?
[ December 13, 2002, 07:26 PM: Message edited by: Havasu Hangin' ]

[Scarab Fast]

My compression ratio is 10.5-1 so 93 octane on the gas. I have only been able to set the timing by the harmonic ballancer so far, 10 btdc. My engine builder said 32-34 total. I have now got to come up with a way to set that. How did you set your total. Idle timing dont really matter total needs to be accurate. Thanks

[Havasu Hangin']

Well be careful with those heads and that compression. The Vortec heads are good for about 2 degrees advance because of the spark plug location...so you are very close to mine. Do you know what size chambers are on those heads?
I have an MSD setup, and running 18 degrees initial, 36 total (all timing in by 2,500 RPMs).
I don't know what kind of ignition you have (and how much advance is in your distributor), but the surest way to set the total is to mark it on the tape on the harmonic balancer, grab a timing light, and rev it to 4,000 RPMs or so...then move the distributor to line it up. If you have a timing light with an advance mechanism, that will work, but I did it the old-fashoned way.
What size cam are you running? I have a 222/230 .509/.530 Crane...which is probably close to yours.

[77charger]

I am curious to see how that drive holds up.when my motor goes out in a few years i hope to do somre mild mods not as much as you guys but at or just over 300hp.I have to see if i have a gen 1 or a gen 2 alpha boat is a 93 elim.

[HP350SC]

Scarab Fast-Keep us posted on what you find is causing your rich running condition.I agree that a 23 pitch prop is a good place to start.Let me know what speed you run when its dialed in.Havasu Hangin-what mph are you running? I believe the vortec heads are 64cc chambers.They are an excellent upgrade from stock 1.94's for the money.Only downside is the intake is a little pricey.I may go the 377 or 383 route this summer,what all do you have on your motor?

[playdeep]

A few years ago I had a 22ft. Tahiti bowrider with a fairly built up 377sbc which in short order destroyed my Alpha.After reading an article in Hot Boat about Konrad outdrives building a beefed up drive to replace the Alpha I went ahead and ordered one.
After two years of holeshots and general abuse I never had any problems with the drive.
The drive itself was only slightly more than an Alpha and was rated comperable to a Bravo...
Might want to check it out as an alternative.

[Havasu Hangin']

HP350SC:
Havasu Hangin-what mph are you running? I believe the vortec heads are 64cc chambers...what all do you have on your motor? I'm not sure about the MPH...I just installed a GPS speedo..which I havn't opened it up with yet. Doing the math, maybe around 60MPH.
That's what I thought about those Vortec chambers...if so, that's alot of compression w/10.5 to 1 pistons...I'd be careful.
My combo is a SCAT crank, Eagle rods (5.7"), and TRW 10-1 pistons. I went with some ported Edelbrock Performer RPM heads (72cc chambers), Crane hydraulic roller cam, and gold race roler rockers. Holley street dominator intake and a Holley (800CFM) carb. Full MSD ignition w/limiter and start retard module.
It pulled 457 HP and 466 ft-lbs with dry headers and 34 degrees total. I bumped it to 36 total, but I also run octane booster, or 100 octane when I'm in Havasu.
With my old Tugboat, you'd swear there was a big block under the hatch...what a great little mouse motor combo...turn-key evertime, and not so much as a hiccup.
I think Phaff builds a nice N/A 383 SBC...I think he gets over 500HP at under 6,000 RPMs, but he uses some Brodix heads (200cc intakes, I think).
I pinged my last motor to death, so I am a little wary these days...

[eliminator777]

My question for you are?
1. how did you set the floats
2.how much fuel pressure
3.do you have over flo tubes in carb's
with out knowing these facts it's hard to guess.
Oh yes are the needle seats sprung?

[West Coast Dave]

We ran a 377 and liked it much better than the 383 combo. RPM's alot quicker plus you can use your 350 fluid damper and flex plate. Our combo was COLA crank, Lunati rods, BRC pistons (14:1), Comp roller cam 256 266 .635 .645. After much research and questions we went the DART steel heads 230 cc w/ 2.08 1.60 valves, Victor Jr w/ a 750 DP. Motor was reliable and would pull HARD to 8200-8500.

[Scarab Fast]

I will give you a brief run down on my motor. 350 roller block, scat 400 forged crank, eagle H-beam rods, dished forged hyp. pistons, vortech heads ( 906 casting #, earlier ones that was built in the states before going to mexico, flow better ), Stainless valves and screw in studs, hyd. roller cam ( not sure of the specs. right now, do not have the sheet in front of me on it ), Craine gold roller rockers, performer rpm intake, Holley 750 HP double pumper carb with J tubes for over-flow, new stock mercruiser ported manifold with stainless Imco risers with 4" thru hull exhaust. The block was filled about half way up the freeze plugs with block fill for insurance and security on the grinding done on the block for the H-beam rods to clear especially with the 400 crank's stroke. The crank, pistons, and rods were all ballanced. The richness problem was the needle was stuck, in the secondary bowl ( probally some grit out of the fuel line) allowing gas to just dump into the motor. I took it out,found it stuck, freed it up, put a little wd-40 on it, put it back in, and put a second Filter in the gas line. No problems since. For float level adjustment I put in clear sight plugs in each bowl, makes it a lot easier to adjust and less mess. I then adjusted the needle and seat to the gas was at the bottom of the sight plugs. While doing this you have to run the motor to run the gas out to adjust to the new adjustment. My speed so for is 67-68 on gps with just me and about 50 gal. of gas. I am turning a 25" prop but it will only turn up to 4600 rpms trimmed out. It comes out of the hole like a 350 with a 19" prop. This shows how strong the motor is but it needs to turn more rpms, 5200-5600 I'm thinking. My next trip out I am going to try a 23" in 2 different diam. and see how that does. Is anyone familiar with a cleaver prop and there ups and downs? Sorry so long but hope I answered some questions and gave some info. Merry Christmas

[HP350SC]

Scarab-glad to see you got the carb. fixed.Are you using a 25" laser or mirage prop? I think you'll find a 23" laserII will work the best for your application,it will give you more trim,bring the r's up a little,and be easier on the alpha drive. I use a 25"high-five,as the diameter is only 13.25".My hull is slow,and I can trim the s*!t out of it. Although....you are making some good torque there,might as well try whatever you can.

[Ronnie]

Scarab Fast
Did I understand you correctly? You are running an Alpha drive? I am building a motor that is very close to yours but I am going to use dart heads. Iron Eagle 180cc 64cc chamber. I am looking at about 400 hp and 450 tq.I have been woried about the drive. I have an older boat as well. 22' Concord. Please let me know how your drive holds up. Thanks Ronnie :confused: