Yeah, it's the last 3 digits of the casting number on the head, that tell you the basics of the head you have. 520 is the 283 Power Pack head, 186 casting would have 2.02" intake and 1.60" exhaust valves, and so forth.
Before the cam can be chosen, you'll need to acquire the transmission. Then the question of automatic vs. manual will be answered. Actually, it would be preferable to get the truck, too. Is there a weigh station on a highway near you? You might be able to have the thing weighed there.
To get an idea of what head work will cost, just call around to your local machine shops. Take a look through the Yellow Pages, and call a couple different ones. If there's a race track in your area, or any racers, find out which shop they use. You won't need (or even want) a major port/polish; what you're after is a good general clean-up of the ports with some blending of surfaces in the area of the bowls of the ports, where the A/F mixture turns the corner.
This is easy to do! Just figure out which shop is the best for your needs, tell them what you are after as far as performance, drop your heads at their door and they will do the rest.
Velocity of the air is critical - you don't want the ports hogged out to get those big numbers on a flow bench, because that's not where the engine is going to be running [high RPM] most of the time anyway. When air velocity drops, fuel can drop out of suspension and start to puddle around the port walls, and it doesn't do anything for power!
For top street performance, all the major pieces need to be present (engine, trans, chassis) to see what you have to work with. The hottest hot rods have been completed on paper before they took shape in the garage - because of the thought and design work that went into them before they simply became another money pit. This doesn't mean you're stuck before you get your truck and the trans - but you do have to know some things for sure before you start laying down ca$h for things like camshafts and headers!
For instance, if you decide you're going to be using the 700R4 with a shift kit and 3.5 rear end gears, but all the sudden someone gives you a killer deal on a T56, that will make a big difference in which cam is optimum for your application. And if you've already laid your money down for the cam, well, you get the idea.
More later!
