gr8shot
Seaman
- Joined
- May 30, 2019
- Messages
- 73
Sounds like a fun project
The cam in a 5.0 and 5.7 mercruiser carb engines have the same part number -431-811658 so you could swap the cam and lifters if the oil in old engine isn't water fouled. Alternative I suspect the truck cam will work fine as well.
A couple of other thoughts -
there are cast iron 4 bbl intakes available that might save you $125 vs an edelbrock. The 1409 will work well for this application and is easy to tune based on reading plugs.
If the block was cracked I'd plan on replace the exhaust manifolds and elbows as they likely froze too. I think the flywheel and harmonic balancer are different between the 5.0 and 5.7. If yours came with a stick shift flywheel that will work though.
The 5.0 and 5.7 are typically offered with different drive ratios, very likely you will need to step up 2" in pitch to keep wot rpm in line. When I swapped my 4.3 for a 5.0 for the same reason I kept the 4.3 ratio drive just went from a 19 to 21 pitch.
I ran the motor for a bit, manifolds looked good, no cracks or leaks at all, so I'll keep them. Water just leaked out of the block lol. Can always get new ones later if I do find a crack. But for now I winterized them since it's getting cold here.
The reading I've done says that as long as I'm replacing a vortec motor with another vortec motor, I can swap out the flywheel from the 305 to the 350. Should be the same for the balancer. I believe both motors use the same crank.
How would a fella go about checking what drive ratio I have? Is it stamped or listed on the drive somewhere? Or how do I figure that out? It's got a really nice stainless 4 blade prop right now. Would be a shame if that won't work for me.