1979 360 small block and heads deal???

It sounds like a good deal to me.
The 727 use's a tad more power than a 904 which is also a tax lighter. Ethier will do.
The. 8-1/4 is the min. Size to have. It is also a good bit cheaper than a 8-3/4 or a DANA 9-3/4. The 8-1/4 will hold 400hp easy.

As far as building up the 360, look into KB Hyper-U's
The MP replacement 340, a nice upgrade over the stock 340 cam will get you to 350 HP with stock heads.
A cam of [email protected], bowl ported heads , will get you 400 HP with a RPM & 750 carb. Headers of course on each listing.

Go to summit racing and find the engine mounts for the swap. There cheap if your yea fits. Or it is the Schumacher swap kit. A V8 rad to cool it is good and you'll need to shorten your drive shaft with the new rear. A throttle cable and kick down cable. A good stall converter to matche the cam.

IF headers are not in the plan, look to Comp cams for the dual energy cam designed for exhaust manifolds.