Some 340 Questions

Ok, excuse me if I rehash anything said long ago, BUT, I have this 1964 Barracuda, and the 273 that originally graced the engine compartment is long gone, a few owners back, and in it's place now sits a relatively strong 340, from a 1970 Duster.

I plan on freshening up the engine, the freeze plugs seep right now, and there's no room to get to them, so the engine has to come out, and as long as it's out, might as well give it a once over(rings, bearings, cam, yeah cam, nice lobey cam).

My question, where on the heads do I find out which kind of heads it has, and what are the advantages/disadvantages of the j heads and x heads?? Shoudl I junk these heads and go for nice higher flowing aftermarket heads(as long as they are available) or sit down with a die grinder and open up the passages on these?? Also, roller lifters/rockers or flat tappet, which is a better choice??

This vehicle WILL NOT be raced, just want a nice strong engine, something decent to go to shows and cruises.

Oh well, for my first question, be gentle with me.....(8^)*
Author: admin