You know, the 327 Chevy was just about GM's finest moment in their long history. I've hotrodded 283s, 327s, 350s, 400s, 396s, and 454s over the last 35 years, and I prefer a 327 hands down to all the other engines. You can make a 327 scream with just a little bit of work. The 3.25" stroke is just about ideal for the 4" bore when it comes to a sweet combination of torque and rev ability.

Anyway, a good head to use that is probably still plentiful and cheap is the 144 (I think that's the casting #) head from '69 and '70 350 pickup applications. The heads have huge smog-type chambers, decent sized ports, 194 intakes, and the accessory mounting bosses on each end. The big chambers work better than you might think with flattop pistons. You'll probably end up with a compression ratio in the 9.1 to 9.5 range depending on head gasket choice.

I used a set of these on a .040 over 350 with flattop pistons and a stock 327/275hp cam on an engine I built in '84 that went into my '70 1/2 ton Chevy. That engine ran unbelievably strong with a cast iron Q-Jet intake, Q-Jet, and cheapo headers. I ran a stock Turbo 350 with 3.73 gears in the punkin. There weren't a whole lot of rides that could take it from a stoplight in the two years that I drove it. Unfortunately, the .040 rebuilder block that I used couldn't stand the gaff, and I lost a piston in one cylinder after a bad overheat episode.

My point is, the old smog heads made plenty of power and torque with no more than a valve job from a local machine shop. They would have done just as well on a 327 as they did on the 350. Back in the day, we didn't buy new heads unless we got the slant plug 202s or turbo 202s (which were totally unfit for street use). Even in '84, high performance heads like the 186 were practically nonexistant in the boneyards or head rebuilders' shops. Older heads from '67 back don't have the accessory mounting bosses on the end, so your screwed if you need to mount an alternator or ac compressor on a later model vehicle. Sure, you can change over to the earlier mounting setup, but you cannot believe the headaches you will run into finding the stuff and lining up the belts. It's a lot easier to get heads with the mounting bosses to start with.

As for weak bottom end torque with a 327, I wouldn't worry about that. My '67 Nova SS has more than enough to keep the tires lit all the way to 3rd, if I'm dumb enough to hold it to the floor once they break loose. It is a 327/350hp running through a 4spd and a 3.73 posi with nothing more than a Holley 650 double-pumper and a set of Hooker comps. I would say the engine would probably run just as well with a good automatic, and it might be a little easier to get the power to the ground instead of smoking the tires uselessly. I've always had to feather the throttle in 1st to even get the thing out of the hole, or lose to the other guy right there in a cloud of tire smoke. A 327 makes plenty of torque for a shortbed pickup.

Another plus about a 327 is that you can keep right on revving while the other guy has to shift his 350, or 396. or 454. They'll spin to 6 grand easily, and that's where they make their power.
If you do decide to use aftermarket heads, I would personally stay away from aluminum for a street application. They are pretty and lightweight, but they will corrode into nothing without running straight antifreeze in the block. They also have a wicked thermal expansion coefficient (all aluminum engine parts do) which may or may not compromise head gasket sealing in your engine.

I really would consider old iron heads both for the expense factor and the durability factor as well. You may have trouble running over 9:1 compression on the street anyway with the available pump gas. Compression won't hurt torque, it'll just limit horsepower in the upper rpm range.

You ought to go ahead and build a sweet 327, you'll be amazed at what fine engines they are.

Randy