21' cobalt repower 5.7 to 8.1
#11
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Re: 21' cobalt repower 5.7 to 8.1
Chevy Performance sells a crate 383 that pumps out 425 hp and has been installed in at least one boat that I know of. Biggus has a friend with a Cig 28SS and dropped two of those into it.
And yes, this engine is good in a marine application.
http://www.paceperformance.com/index...D&ProdID=73193
And yes, this engine is good in a marine application.
http://www.paceperformance.com/index...D&ProdID=73193
#12
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Re: 21' cobalt repower 5.7 to 8.1
Originally Posted by SeaRay Jim
But don't listen to me...I have a new 540 under my hatch.
I also saw the video with that fellow standing behind your motor on the ground! Awesome! That thing sounds bad to the bone!
It will be fun to see how she runs on the water!
Kent
#13
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Re: 21' cobalt repower 5.7 to 8.1
I think Bob FTM) did a 350 or 6.2 Whipple setup on the 21 Cobalt. Said it felt like a dragster but was a handful past 70 .
Maybe he'll chime in here.
Dave
Maybe he'll chime in here.
Dave
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Re: 21' cobalt repower 5.7 to 8.1
Originally Posted by cobaltboater
WV and SR J , Thats cool but I would like to keep my mpi fuel setup . So what cam will do it and what heads? Ive been looking at stainless marine exhaust. I would like to go low 70's and be reliable. I would think thats alot to ask for with a smallblock.
If you're willing to go to aftermarket EFI then you may be OK, but prepare to spend another $3000 or so.
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Re: 21' cobalt repower 5.7 to 8.1
Originally Posted by Mudball
I stopped by FTM yesterday and checked out your new motor!!!! Indeed it was in the boat!!!
I also saw the video with that fellow standing behind your motor on the ground! Awesome! That thing sounds bad to the bone!
It will be fun to see how she runs on the water!
Kent
I also saw the video with that fellow standing behind your motor on the ground! Awesome! That thing sounds bad to the bone!
It will be fun to see how she runs on the water!
Kent
The video does sound good. However, turn the sound off and just watch. Now imagine a headline reading something to do with the Darwin awards. LOL When you stop and look at him sitting there on the office chair behind the motor, I can just hear someone yelling from the back ground, "hang on, don't let go, DUUUDE, this is gonna be cool as chit" And then, "OH CHIT, what happened? Call 911!!"
LOL
Last edited by SeaRay Jim; 02-15-2005 at 02:48 PM.
#16
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Re: 21' cobalt repower 5.7 to 8.1
Jim, I hope for you that the weather holds out!!
If you do head down here, you'll see my boat as well...Bob's doing some 'stuff' to it, that I can't do (I'm gettin too old)...
Best,
Kent
If you do head down here, you'll see my boat as well...Bob's doing some 'stuff' to it, that I can't do (I'm gettin too old)...
Best,
Kent
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Re: 21' cobalt repower 5.7 to 8.1
Originally Posted by Nordicflame
I think Bob FTM) did a 350 or 6.2 Whipple setup on the 21 Cobalt. Said it felt like a dragster but was a handful past 70 .
Maybe he'll chime in here.
Dave
Maybe he'll chime in here.
Dave
I don't remember the details, but he is reworking a 350 for a 20 foot Crownline now!!!!
Fun stuff!
#18
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Re: 21' cobalt repower 5.7 to 8.1
Cobaltboater, I'm very familiar with that boat. I have a customer with a 6.2 in a 206. The first year I modified the engine. Ported heads, bigger cam, aftermarket EFI, stainless marine exhaust. We picked up 6-7 MPH. That wasn't enough for him, so the next year we added a Whipple to that package. It's now producing 600+HP. The problem is you can't drive the boat past 70. It is the scariest boat I've been in. We ended up just putting a lower pitch prop on it and setting the rev limiter at 5400 RPM. It is a blast to drive though. It feels like a drag boat. What I really can't believe is that the stock Bravo drive has lasted 2 years. I have the aftermarket EFI system we took off. It's for sale. You would need an aftermarket ECU to go with it though. I use a FAST system. The stock merc EFI just won't make any HP