I have a motor upgrade opportunity

[kc0000]

I have found a complete 502 Mag MPI Gen VI with only 40 hours on it, and a crack in the block due to cold weather. This could turn into a nice winter project for me.

I'm very hand with my tools, though it has been about 15 years since I totally tore down a motor and brought it back to life. All in all I should be able to get the motor and a new block for about half the cost of buying a used motor, maybe around $4300.

My simplistic thinking tells me that I should be able to buy a new block, hone the cylinders, swap all of the components while replacing all of the gaskets and the piston rings. Yes it will take a few hours..... another and probably better possibility, is to have a pro-shop build me a short block.

Any comments or concerns from the peanut gallery?

Any reccommendations for a pro-shop?

Thanks,
KC

[BADFISH II]

I know how to turn my key and make the boat go, sometimes I even remember to pull up my drive when pulling out (ha ha), but that's about it. Sounds like fun though!

[digginfordollars]

That 502 MPI is (I think) 415 horsepower. Still better than the 7.4 though. What about a procharger on the 7.4? If you stay somewhat mild you can still get pretty good reliability out of it for slighty less money and your hands will be cleaner.

[digginfordollars]

Don't get me wrong though, it sounds like a great winter project!

[Essex502]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (kc0000 @ Aug. 01 2002, 10:28 am)</td></tr><tr><td id="QUOTE">I have found a complete 502 Mag MPI Gen VI with only 40 hours on it, and a crack in the block due to cold weather. Â*This could turn into a nice winter project for me.

I'm very hand with my tools, though it has been about 15 years since I totally tore down a motor and brought it back to life. Â*All in all I should be able to get the motor and a new block for about half the cost of buying a used motor, maybe around $4300.

My simplistic thinking tells me that I should be able to buy a new block, hone the cylinders, swap all of the components while replacing all of the gaskets and the piston rings. Â*Yes it will take a few hours..... Â*another and probably better possibility, is to have a pro-shop build me a short block.

Any comments or concerns from the peanut gallery?

Any reccommendations for a pro-shop?

Thanks,
KC[/QUOTE]<span id='postcolor'>
I'm an old drag racer from way back and busted the knuckles a few times turning wrenches! My recommendation would be to let a professional prep a new block and assemble it yourself. I find that kind of work very satisfying but can't seem to find the time to do it any more. Buy the pieces and let them fit the pistons and crank and you do the assembly.

Do you have a Bravo 1 or Bravo 3 drive unit? Might make a difference for longevity with the 502.

Though I like the idea of the Procharger or Whipple or Vortec route if your motor is in good shape. Less work and you don't have to take the motor in and out of the boat.

[kc0000]

Thanks guys.... grest ideas and points...

I'm looking for more kick without attempting to stretch the connecting rods. I'm not looking to extend the factory rev limiter on either motor.

Bravo 1 22P

This is a quandary.....

The 7.4 MPI would do well with a Whipple from ccperformance for about $4200. My concern is the lower end, crank bearings and two bolt mains. Plus there could be some blow-by past the rings, no big deal.

As I understand the 502 has MUCH better internals and 4 bolt mains, so no worries. Adding a Whipple to this motor is very safe!

If I go the 502 route, I will probably have a few bruised knuckles and allow a pro-shop to put together the lower end... Also, I will have a complete 7.4 MPI that I can sell to help offset the costs of the 502. The 502 motor will be bullet proof.

If I go the Whipple route on the 7.4 MPI, then I am adding an additional component with moving parts, on top of a motor that was not designed to handle the extra air and power.

Either solution would give simular amount of torgue and hp, the 502 would be bullet proof, the 7.4 with a Whipple would not last as long as the 502.

Either way my Bravo 1 should be fine and I need a new prop.

Not worried about the time it takes to turn the wrenches, I'm single so I have all the time in the world to putter in the garage this winter.

Help me out guys............... what have I overlooked?

Thanks,
KC

[digginfordollars]

I like the 502 with the whipple, but then your really extending this low budget project. If you build the 502 and the sell the 7.4, you would have a nice motor for very little actual investment. Go for it!

Contact Rick Cameron at Manor Marine, Parker AZ,760-655-1051; tell him Dennis Dawson told you! He has built 2-454 Chevy motors, 1-468 Blown motor & 1-Twin Turbo 460 Ford motor for me. He has a Top Fuel dragster he runs and is a master at motor building. He stands behind his eork and won't kill you on price!