That's a pretty good price for the complete 390, but I'd get casting codes first and pics of the block or if you can look at it. If you look down the bananna slots at the front and rear of the head mating surface and see 428, then you have a block that will likely go to a 4.13 bore. Having an A or a C scratched into the rear sand core (will look like the letter has been welded on the rear of the block) is usually indicative of a 428 block as well. You need head casting numbers as well. Some of the heads will flow better than others and you need 14 or 16 bolt holes in the exhaust flanges or at least have the provisions to drill and tap these locations if nothing else, so early heads won't work (you have to use the diagonal bolt pattern, not the top and bottom pattern on a Mustang). If the heads are C6AE-R's or C80E-N's, they are worth some money to the SS guys so you'd be halfway to a set of aluminum Edelbrocks or even most of the way on a used set.
A dressed out FE only weighs 60-80 lbs more than a fully dressed out 351w.
A stroker kit for the FE will run about $1600 for the crank (cast) , rods (H or I beam) & pistons (hyper or forged) which is about the same as a 351w kit. The block needs no notching with the 4.25 stroke crank and if you buy the Pro Gram Engineering cross bolt main caps, you can have your block machined and be just as strong as a 427 block. These can typically go in a 390 to about 445 cubic inches. That bottom end would be pretty safe to 600hp.
C8AE-H heads are pretty common and can be ported by a couple of knowledgable guys for pretty decent price that will flow well (Scott Vincent and Les Schmader). An RPM intake is a nice dual plane intake that can be made to flow really nice. The Victor intake is a good single plane, but for some reason, they always need a LOT of work to run good. It's not a bolt on and run intake, it MUST be ported and sometimes decked as the valve cover rails aren't always level to the heads.
The stock rods are up to the task as well. Several companies make nice roller rockers and you can lose with the stock shaft system. There are some oiling mods that need to be done to the block, not expensive but detailed and consume a little time.
I'm planning a budget 390 performance build without a stroker kit that I'll detail out one of these days as it's built. It'll have ported iron heads, an aluminum dual plane intake, solid lifter cam, roller rockers, prepped stock rods and higher compression pistons. Cam, rockers, intake and pistons may even be used (and I hope they are). I'll have it dyno'd when it's done. There will be no swapping of headers or carbs, just get it in it's best tune and run it.
Oh, a 428 crank will also work with a set of 410 pistons IIRC.
