Coilwire,
I believe the Crites lower mounts are configured to be used with the 71 429 style mounts that are two piece with a plate & insulator. I recall a similar thread here that discussed using the one piece 429-460 mounts that bolt directly to the block from a big block Torino or LTD. They end up with incorrect clearances for exhaust, clutch linkage, etc. Another thought is that Crites are solid type mounts. I would suggest to use a total package whether its all Ford or all Crites, I am currently using all Ford type in my car with 4speed & stock cast iron manifolds with no issues.
Thanks, Jay