I went to set the lifter preload on my new engine and some of the pushrods are popping out (pushing toward the top) of the hyd. lifter cup after a revolution or two. Not all push rods are doing this. I used a pushrod length checker to get the proper pushrod length. They ended up being 8.150". I thought that was quite short compared to stock 8.40, but I did have .025 taken off the block to square things up. The heads are CC 4V's that I got rebuilt from a guy for $400. He said they were "Race Prepped". I had one head CCed at 65cc, so I know that the heads weren't cut, but they were modified for screw in rocker studs and some material taken out of the exhaust port. Could the machinist have messed up cutting down for the screw in studs that would be causing the pushrods to not seat correctly?
Also, the heads had 3/8 guide plates on it when I got them and I just switched to 5/16 plates to match my pushrods. Would this cause issues too? I measured the plates and the new plates are only .008" thicker. (.106 vs. .098).
These $400 race ready heads have already cost me new guide plates, new studs to fit Harland sharp RR, new springs to fit my camshaft, labor to CC the heads and custom pushrods. I've spent about $1200 so far and now I think the head machine work could be messed up.
Let me know what you guys think.