1961 sm420 to zz4 crate motor

[joe dirt]

im looking to buy a zz4 crate motor for my truck and want to keep the sm420 trans, I know ill need to source a flywheel and clutch for that year of motor and possibly a starter as well, but what about pilot bearing or whatever else....has anyone here done a 1 piece rear engine and retained the sm420 trans??

[andyh1956]

I think I have what you're looking for in my vast archive of semi-valuable parts stash. PM me

[Captainfab]

Do they still sell the ZZ4? I know GM is up to a ZZ6 now.

I am assuming you are keeping the stock bellhousing? If so, you are stuck with the bellhousing mounted starter. Just get the high torque version. You'll need a 168 tooth flywheel for a one piece rear main seal small block. Then just a good quality 11" clutch. Nothing special for a pilot bearing, just a standard bronze pilot bushing

[joe dirt]

captain....no the zz4 isnt mass produced anymore...but since my 383 build kinda took the low road...ive decided to find another option....found a good zz4 locally with only 30k miles complete carb to pan for just over a grand...plans now are to upgrade the heads and cam and shoot for an honest 400hp

[Captainfab]

That's a decent deal for $1K. I believe the new ZZ6 puts out 405hp? The shortblock is the same, just the better Fastburn heads and a bigger/better cam.