How much clearance should be between the rocker arm and the rail(pipe)? Mine seam to have about .020" slack, were they made this loose or is mine wore out?

Also need a good source for new heads, mines cracked.

Just had mine a part, rockers were made loose. I bought a reman head from Huckstorf. It was a GM casting. Kenedy or SS have good ones (according to comments).

When I researched and I saw a lot of cheap ones, chinesse castings, also read some real unkind comments about the cheap versions.

Do some seaches on cylinder heads and do a little reading. Theres a lot of comments on the DP.