Ok guys we've been busy and haven't been posting but here is our latest project arrived yesterday we're building a pair of twin turbo big block aluminum chevy EFI engines they're going to be 380 ci as planed so far and we expect to make in the 1300 t0 1400 hp I'm going to document and show as much as possible and at the end we'll see how close we come . The customer wants to run 170s and have the fastest accelerating boat he's aver had we're going to give it our all . Also all the wiring for the dash panels we'll be finishing for him. Hope you gear heads enjoy . Sincerely Laz Mesa

Laz, 380ci?

'380 ci' ?

Hi Laz: You must really want to rev those puppies! I know this is sometimes necessary with available props and ratios to get the big speed, but I'm thinking about Mercury's 500 CID race engines that used 4.6 bore with 3.75 stroke. Wouldn't that work or does the customer want to base this on an engine program developed for under 400 CID racing class?

We've been building turbo engines for years now for drag racing and I have several customers that have broken every E.T. and mile and hour record in their classes for years this is going to be one bad set up we plan on turning the engines 8500rpm with the gear we have in the drives to see speeds in the high 160 to low 170s I'm going to show flow numbers rod ratios cam specs and at the end the final dyno videos and dyno numbers.

There are plenty of Turbo Diesels running out there in the marine environment.

A 380 c.i. big block should be absolutely bulletproof!

At 4" bore x 3.75" stroke, you are going to have a mean piston speed of over 5300 ft/min at 8500 rpm. That doesn't seem sustainable. My suspicion is that you must be cooking up something like 4.5" x 3", which lands you squarely at 4250 ft/min MPS. Am I far off?

Has a motor of these dimensions been built before? Could this spawn a new trend for supercharged motors as well? Why not run around with bomb-proof blower motors at 25 psi of boost too? I guess your big challenge is going to be building a valvetrain that can hack it. The poor exhaust valves are going to get hit 4250 times every minute with the turbo's blowtorch.

Can't wait to see!

The've been using twin turbo motors in the boats that pull speed skiers on the west coast for years. Everyone out there uses them. I dont know the specs but I think Pfaff started the craze many years ago. Ive seen them accelerate and they are quick!!!!!

GM was workong on a marine engine test program a few years back- As I recall it used a BBC block with short stroke and was less than 400 CI. The heads were special, and were seperately cooled independent of the block. They made big power, but time and patience wore out. They built a couple of prototypes, and the whole project got shelved.

Powerboat magazine did a story about that engine a few years ago. I still have it somewhere. The engines put out big power but the outdrives couldn't take it. That was before #6 outdrives. Btw, the guy that built the exhaust for that boat lives in my neighborhood and does welding and fabrication still.