Time for a New big block

[MRomeo430]

Last year I bought my first Mastercraft a 89 Maristar 240 with a 454. I bought it running rough and found out my heads were shot ( at least 3 cracked intake runners). Now I'm replacing the whole thing because if it was overheated I won't chance it. I'd like to do a long block set (got a set of old heads from a friend). So a few questions:

1, Mastercraft can't search my HIN it's a year too old, says my HH means 425hp 454 with a 1:1 and a one inch shaft----can anyone confirm this?

2. Anyone have a recommended place to get a long block and parts? (I've been looking at USengines.com

3. Want to rebuild my trans while im in there (had water in the fluid last year) anyone recommend a kit or place to buy one?