Newbie (sort of) needs some ideas...

Moper:
For what you want to do, any slant six engine will work just fine. If you use a 68 or newer engine/crank, all you need is an inexpensive adapter bushing to go in the end of the crank and the 68 or newer flexplate. Just find a rebuildable 225 engine, increase the compression ratio to about 9.0 to 9.5 to one. which can be done by milling the head, while the valve job (bigger valves and hardened exhaust seats) is being done. Cam needs to be selected depending on whether you will change the converter stall speed, and balanced with the compression ratio. Bigger cam will require more CR, then a smaller cam. Up grade to electronic ign, using a chrysler electronic distributor, and a GM HEI module with either a HEI or Ford "E" coil. You will want to recurve the distributor, after you get the engine running and see what it wants. My 66 Valiant with a stock shortblock 225 (with cam), and just a milled head and good valve job (stock size valves), turns the 1/4 mile in 14.8's sec, on motor only, no power adder. No machine shop work on the engine except the head. Here is a link to the build.
http://www.slantsix.org/forum/viewtopic.php?t=11218&postdays=0&postorder=asc&start=0

Grinder, lets not start a pissing match, please. Moose was actually making a valid suggestion. If course I wouldn't do that. I removed a 360 from my Barracuda, and installed a 170.