Big Block Billy

HELLO ! My friend has a 38' Scarab with '95 330's Merc trans2's and Trs drives. Drives were rebuilt and transom assemblies replaced. I rebuilt one of the motors with hyperutectic flat top pistons, Resized rods, arp bolts, 10 under cast crank, and of course had it balanced by a reputable shop on a brand new machine. My question is if the motor I rebuilt is strong enough to run a blower. Do I need to rebuild the other motor? Should I get forged cranks? Forged pistons? Should I even bother messing around with the Gen5 454's. I have several sets of mark4 heads that could retrofit with a special gasket. We are prepared to convert to the velvet trannys ! I really don't want to see him waste money, so if anyone has any good advice it would be greatly appreciated. Maybe he should start off with bowtie 502's or even buy a pair of 540 shortblocks ready to go. The boat does 59mph GPS the way it is. I still have a gen 5 rebuildable core to play with too. Another option would be for me to build mark4 mag motors out of parts I already have, and sell the gen5's. I've been reading up on blowers extensively, and it seems like an easy way to make power. I don't want to make any mistakes if thats possible Thanks in advance BBB

tripps

Dont bother us,Daytona is on Tripps

Big Block Billy

WOW ! HEY ERIC (TRIPPS)
I was thinking of going over to see you with a case of Corona's and tapping into your vast knowlege. Or even abducting you for a while to check out this boat (it's awesome) drool: with a possible (probable) pit stop at the bar. BBB:

tripps

Read above post DAYTONA IS ON !!! and after that i have to go to a function with my son and boyscouts,but anyway go and checjkl; out ebay#2460614653 sea ya tripps

marinetrans

First thing I would do convert to B/W set-ups. Then I would replace the old style high pressure trim systems w/ new style high volume trim systems. The drives will react faster when trimmed. External steering helps too.No more lose gimbal rings.

Crazyhorse

This is just my opinion, but as long as he's not looking to keep the throttles jammed against the forward stop, and if the boost is limited to 4-5 pounds, he'd be able to run blowers. The smart thing would be to build a couple mild forged-piston motors while he's getting the feel of the blower-equipped motors.

Big Block Billy

Thanks, Marinetrans.
The boat has the external steering already and has the newer trim too. It was hard to get parts for the steering, it's Mercruiser and it's discontinued. We had to buy a complete setup used for $1000 from some yard in Florida. All we needed was the cylinders(corrosion). And to Crazyhorse: how much power can be attained by running with 4-5 lbs. boost? I'm doing most of the work (all of the technical work) and really want to do it once and do it right. This is one of many boats I'm servicing, and have other jobs lined up. I really would like to hear from more people , Maybe then I can decide what works best, and create usuable power with minimal breakdowns or overhauls. Thanks, BBB

puder

you shoudl be able to make high 400 maybe 500 hp with 4-5 lbs of boost.

Big Block Billy

Puder , Would you actually do this, install blowers on motors as they are ? Should I change heads and at least get rid of the small port, small valve heads. Also the valve springs probably aren't good enough. I'm thinkin' about putting mark4 049 or 781 heads on the motors with the Felpro 17046 or 17048 gaskets (I have to check #) so I can use Mark4 heads on Gen5 blocks. I have several sets of heads already to go, complete with 2.19 & 1.88 severe duty valves , 550 lift Ls6 springs. Is a cam change a good idea ? Check out WWW.jrcblowers.com They make billet end plates and are a wealth of knowledge. It seems that if I used forged TRW 2377 pistons I could run 8lbs boost, with a final ratio of 12.4 Maybe a teardown is the way to go. BBB

Big Block Billy

Also Maybe I could dissasemble the motors and have the other one balanced and re-sized with arp bolts. I could probably have them match the new piston's weight to the hyperutectic ones in the motor that I rebuilt, And run forged pistons in both. What do you guy's think, Is it worthwhile? Maybe I should just make up a pair of 496's being that I'd already have to buy pistons and tear down and balance. Maybe I should sell the motors as they are, They run great and are perfect, new Merc. manifolds etc... and just save the accessories. Too many options... But I have many parts. Maybe I should build blower ready motors and just do a quick swap out along with the tranny's The motors have to come out to change tranny's anyway. It all depends on how much $$$ he wants to spent, I think he's good for it. Also maybe I should go with dished pistons for greater swept volume. I was thinking 540 ready to go shortblocks, but they will probably need bigger blowers and better heads than what I already have. This project really requires much thought. BBB , Thanks to all