5.3 iron block
there is quite a bit of info available on this forum to read on the subject. do a search on the "Generation III Internal Engine" section and you will find some good answers.
The iron 5.3 block can be bored to accept the larger pistons in the 383 kit (3.905" vs 3.780" bore), however the machining cost will be around $300. This is the setup that I have.



