I'm looking for some suggestions regarding engine choice. My 50 F1 has a 255 Merc Flathead with a four speed trans in it now. The flatty leaks like a sieve, and the four speed limits me to about 50 mph.

But...... It's cool! I love it and want to keep it, but I'm afraid I'm gonna get a grand or two into a t5 swap, 9" rear end,and Toyota PS conversion and find myself with a crapped out flatty that will cost $3K to rebuild.

My question is; Do I move forward with the aforementioned upgrades and replace the seals and gaskets on the flatty, or do I go ahead and pull the trigger on a 302/AOD swap. I can probably get into a new 302 for about $1000-1500.

I wouldn't be so hesitant about just sealing up the flatty, but it seems it may have some issues more than just the leaks. I'm getting a good amount of blow-by when I start it, and I may also have some valvetrain issues.

I wouldn't be agonizing over this decision if I didn't LOVE my flathead so much.

Thoughts? Opinions?