360 build recommendations

The H116cp Sealed power pistons BJR mentioned are very close to the stock piston weight so if you use them it shouldn't need balancing but it's still not a bad idea. If you use the KB107 pistons you will have to balance the engine because they are much lighter than stock. The only concern I would have is if the heads are shaved any and the block is decked any your compression ratio will be up close to 10 to 1 (if not over) with either the C116cp or KB107 pistons which is pretty high for 91 octane fuel, especially if you run a smaller cam like the xe268 Comp or 60403 Lunati which develope more low end cyl pressure.

I have a 360 with the KB107's and X heads and a 60404 Lunati cam and have to run 93 octane with no more than 33 degrees of total timing for example.

If you want to be safe with 91 octane fuel go with Sealed power 405cp pistons that will put the compression at approx. 9 to 1 and run either the xe268 or 60403 cam and a converter in the low to mid 2000 stall range. In your light car it'll run like a banshee and still work good with AC. Just my .02