As far as I know the 502 still in the boat is good. I could buy one for the one missing or go with 496s. I know 496s have alot of torque. I have a 496 in my mud truck. It runs like a scalded ape.

496's have very limited ability to upgrade and most of the parts on them cost more than 502 parts.
Exactly what engine do you currently have?? and which model/year 38 Scarab do you have??

The 502's will have just have about the same torque as Merc 496's. Is the 496 in your truck an 8100 Vortec or a 454 stroked to a 496?? They are completely different on everything.

I have an 8100 vortex in the truck. I have heard the 496 is limited on upgrades. I'm currently just leaving it all stock. Just wanting to get the boat back in the water

the boat I have is a 91 year model. It still has one 502 in it untouched but the other 502 is missing

2 500 efis in swap shop, fresh rebuilds great price, get both, sell your 502 to offset it and go boating...

The 496 is a monster and responds very well to just about anything put to it. The issue is they are getting old, parts are getting expensive. There are very few mid level speed parts. They do last a very long time and under stress. Gen 7 is awesome............but GM went to the 502.......big man speaks.
Id go to 502

cool. I'll look into that

First thing I'd do is see is how healthy the 502 in the boat is and then go from there.

This is bad info, the 496 is not a monster, it is good in stock form and from there take a lot of $ to upgrade if desired. The 502 was around way before the 496 and it is still available. 496 has cast pistons and a lot of them had cast cranks.

Monster and 496 dont go in the same sentence! Take a stock low hr 502 and 496, give them both 7.5 lbs of boost and see what happens .