OK guys, I have no idea how to measure for the correct pushrod length for my 4.1. I have a 291 4.1 block that has not been decked and stock 8445 heads that were not resurfaced. I'm going to be running a Comp 216/218 cam. Gross Valve lift is .485 intake and .489 exhaust if that matters. I'm usinng the Federal Mogel lifters. This is a flat tappet cam. I'm using the stock rocker assy also. Will you walk me through what i need to do and what tools I need. I have no tools to do this job so I'll have to go buy some. The lifters are soaking in oil now. Unfortunately while installing the cam, I noticed the machine shop gouge the rear cam bearing so it needs to go back to get that fixed......I have time to read and buy tools now! I was planning to use the stock pushrods if I can and have been told both ways. Some people say thos pushrods will work, others say they need to be checked anyways. I decided I better check them and it will be good practice for the next motor anyhow! BTW....I'm using Felpro 1000 head gaskets. Thanks for the help guys. ----Jeremy