got a question about a future V6 to V8 repower...

[Tail_Gunner]

The 5.7 is the way to go. Hp diff between a vortec 4.3 and 5.7 is 225 vs 295, torque diff is 268 lb ft vs 370…and the torque curve for a 5.7 is flat http://marinepowerusa.com/wp-content/uploads/2019/08/57lspecs.pdf

if you are running a 17 now you d probably need a 21 with a 5.7

Ahh 100 ft lbs, much more than I thought, actually is that not 7.4 territory?.

Which brings up the question, can the drive run that much tourqe?

 

[Lou C]

"I had used both a 15x17 and a 15.5x15 with the V6 to lessen the strain on the V6"

Based off that and your boat I doubt very much if you could swing a 21 on the setup. There is just not that tourqe difference between a 4.3/5.7

At the end of the day it's tourqe that swings props, and you have a heavy boat there. The 5.7 should compliment nicely

Ahh 100 ft lbs, much more than I thought, actually is that not 7.4 territory?.

Which brings up the question, can the drive run that much tourqe?

Yes it can the original Cobras were used behind 5.7 4bbl V8s. They are as strong as an Alpha as far as I know. OMC went to the Baby King Cobra for the 460 Ford which puts out a good deal more torque than the Chevy small block. These drives had the regular Cobra upper gear housing with the stronger Evinrude V8 outboard lower unit.

 

[Lou C]

Lou.....build a 6.2

Scott if I had a machine shop that could help with this, for sure I would, although I think I'd be swapping my Cobras out sooner rather than later lol. Michigan Motorz sells them but they are like 7 grand.

 

[Scott Danforth]

Scott if I had a machine shop that could help with this, for sure I would, although I think I'd be swapping my Cobras out sooner rather than later lol. Michigan Motorz sells them but they are like 7 grand.

no need for a machine shop. you buy virgin bore blocks from GM, and simply assemble in the kitchen for about $5k (was $3500 2 years ago)

 

[Tail_Gunner]

Building your own can be tricky these days, plan it out top to bottom and then you get to track down parts. And that may stun you. Parts house's are backordered across the board. Check a few options before you jump.

 

[Lou C]

That’s one more issue with a project like this. Mebbe when the time comes I just buy a reman V6 short block & put my heads that I installed on the old block in 2017 on that…

 

[Scott Danforth]

That’s one more issue with a project like this. Mebbe when the time comes I just buy a reman V6 short block & put my heads that I installed on the old block in 2017 on that…

they also make a supercharger for the 4.3.....

 

[Lou C]

Given what’s happening in the world right now I might just stick with the economical V6-Quadrajet. Imagine what gas on the water will cost this summer. I could see it hitting 6/7 bucks a gallon at this rate…

 

[achris]

Given what’s happening in the world right now I might just stick with the economical V6-Quadrajet. Imagine what gas on the water will cost this summer. I could see it hitting 6/7 bucks a gallon at this rate…

I paid $2/L this morning.

 

[Lou C]

Ouch!
Well if I wound up with a Vortec V6 I’d have 25 more hp at least

 

[Scott Danforth]

Given what’s happening in the world right now I might just stick with the economical V6-Quadrajet. Imagine what gas on the water will cost this summer. I could see it hitting 6/7 bucks a gallon at this rate…

fuel is still the cheapest part of owning a boat.