desparatley want to swap engines

[Blackbart5]

Engine swap??

Hello, I have a '95 rendezvous 2659 with the gutless turd 5.0. I've been looking for the 5.7 to swap. Question is, is it hard, what does and doesn't bolt up, is it just a basic engine swap??? If someone could go into a little detail, I'm just concerned about the outdrive/transom bolting up......alpha one gen ll.

 

[Blackbart5]

Engine swap questions

Hello...I have the '95 rendezvous 2659 with the gutless turd 5.0, I'm looking for a 5.7 to swap out....will it bolt right up to my transom/alpha one gen ll, motor mounts the same? What would be different if anything?

 

[Bt Doctur]

bolts right in, may have to change the prop or the drive gear ratio

 

[Blackbart5]

bolts right in, may have to change the prop or the drive gear ratio

Yea, I figured I would have to do that do to rpm range difference....I'm being told that I will have to get some kind of aligning tool to make sure my mounts are adjusted correctly for proper angle???

 

[Fishermark]

Yea, I figured I would have to do that do to rpm range difference....I'm being told that I will have to get some kind of aligning tool to make sure my mounts are adjusted correctly for proper angle???

That is correct. Very important step. Go ahead and buy the alignment bar as you will use it from time to time.

To make things easy on yourself, make sure you find a comparable vintage 5.7 engine. (One piece rear main, etc).

 

[Blackbart5]

I did find one...same year/cable bracket location/manifold riser location, same outdrive........I'm a Motorhead, so I understand what you mean by rear main seal but why would that matter on a marine engine? not arguing, lol

 

[Scott Danforth]

I did find one...same year/cable bracket location/manifold riser location, same outdrive........I'm a Motorhead, so I understand what you mean by rear main seal but why would that matter on a marine engine? not arguing, lol

Because the type of the rear main seal determines the flywheel, coupler, and starter. Its just easier to keep same vintage

 

[Blackbart5]

Because the type of the rear main seal determines the flywheel, coupler, and starter. Its just easier to keep same vintage

Gotcha. What about going to a big block like a 7.4? Is that a whole new ball game?

 

[achris]

Dimensionally, the mounts for a 454 are the same as a 350. Same era should get you the right flywheel, coupler etc. The big 'gotcha' is the drive. Alpha can't handle the torque produced by a big block. And the Bravo and Alpha are not interchangeable without other mods. If you want a big block, buy a donor boat and do the full changeout.

Chris......

 

[Blackbart5]

Dimensionally, the mounts for a 454 are the same as a 350. Same era should get you the right flywheel, coupler etc. The big 'gotcha' is the drive. Alpha can't handle the torque produced by a big block. And the Bravo and Alpha are not interchangeable without other mods. If you want a big block, buy a donor boat and do the full changeout.

Chris......

The alpha gen2 wont/cant handle the hp/torque?? Would i have to get a different Y pipe?

 

[Scott Danforth]

Big blocks eat alpha drives and spit out the gears. You need a bravo drive if going big block

 

[achris]

The alpha gen2 wont/cant handle the hp/torque?? Would i have to get a different Y pipe?

A) Correct. 300hp max through an Alpha One (both versions!)
B) Y pipe is the same between SBC and big block.

Chris........

 

[Blackbart5]

Ok....I have a 1995 2659 rendezvous(5000lbs). It has the 220hp vortec heads 2bbl carb 5.0 mercruiser. ID numbers say it's a 1999-2001 block/heads Boat holds 13ppl. It struggles to plane with 7ppl. I sure would like it to plane with 13ppl. I did put the smart tabs on, helps a bit.....with 7ppl, 4500rpm wot......I'm desperately wanting to switch engines. 260hp or higher 5.7....OR 454. It has the alpha gen2. What do I need to know/what/look for when looking for a drop-in engine. I'm very knowledgeable with car engines, lots of schooling......as far as what bolts up to what, change this, change that, you need this/that, will any year work, make sure this is??? These are the questions I need help with........I'm needing direction for a hassle free/non wrench throwing/non cussing engine swap....thanks

 

[Bondo]

Ayuh,..... Go with a 350, '96 or newer,....

If ya go BBC, you'll wanta go pulleys to prop with a Bravo drive,.....

What's yer budget,..??

 

[Blackbart5]

Ayuh,..... Go with a 350, '96 or newer,....

If ya go BBC, you'll wanta go pulleys to prop with a Bravo drive,.....

What's yer budget,..??

I've found several drop-ins for 1500ish in both small and big block......do you think a 260ish hp 350 will do what I'm wanting?. I'd like to keep the price around 1500ish. Here's my thinking....250/60/70ish hp 350, add my vortec heads and aluminum intake (if the drop in doesn't have vortec heads) and that would get me to around 300hp....what's do you think? Would that get what I want for my boat?

 

[Rick Stephens]

If you're going to stick your heads and intake, just get a similar model shortblock. No need for any of the top end at all. You might even consider a 383 stroked shortblock for the additional ooomph.

 

[Scott Danforth]

heads from the smaller bore 305 have smaller valves and combustion chamber than the heads for a 350. ( unless you used aftermarket heads for a 350 on the 305, then in that case carry on, as your performance in the 305 would have suffered from the extra shrouding of the valves from the small bore and the low compression from the larger combustion chamber.

the 305 "vortec" head casting numbers are 12558059 and 12552520. these heads did not get a true vortec combustion chamber
the 350 vortec heads (L31 5.7L Vortec) casting numbers are 12558062 and 10239906.

 

[Rick Stephens]

Thanks Scott, you're da man. I didn't know that.

Rick

 

[Fishermark]

I've found several drop-ins for 1500ish in both small and big block......do you think a 260ish hp 350 will do what I'm wanting?. I'd like to keep the price around 1500ish. Here's my thinking....250/60/70ish hp 350, add my vortec heads and aluminum intake (if the drop in doesn't have vortec heads) and that would get me to around 300hp....what's do you think? Would that get what I want for my boat?

In your first post you mentioned wanting...

I'm needing direction for a hassle free/non wrench throwing/non cussing engine swap...

If you want a simple, dependable, no hassle swap, then I would suggest going with a long block crate engine 350. You can pick up a brand new engine from Chevy for around $1,500, or less if you shop around. The good news is the truck engine has an appropriate cam, composite head gaskets, and brass core plugs. Put your marine externals on and go boating.

 

[Bondo]

If you want a simple, dependable, no hassle swap, then I would suggest going with a long block crate engine 350. You can pick up a brand new engine from Chevy for around $1,500, or less if you shop around. The good news is the truck engine has an appropriate cam, composite head gaskets, and brass core plugs. Put your marine externals on and go boating.

Ayuh,.... No doubt,.....

Order up a replacement crate motor for a '96, to 2000 1 ton or larger truck,....

It'll have the Best of the goodies, like the 906 Vortec head castin's with the ssteel exhaust seat inserts,....
The right roller cam, 'n All,....