Economical replacement rocker arm set?
Great question to which I dont know the answer! I am relying on you guys to guide me through the darkness here. Everything you have me do I am doing for the first time ever.
So far pulling the intake hasn't been necessary since I could pull the lifters through the gaps. Also, I have pulled and replaced the intake 4 times, 2 of which have resulted in gasket failure, so now you the true reason for my hesitation.
Understood. but you can't measure or see the preload properly through those holes.
You may want to try one thing and this is just a thought, I have not tried it myself and it may be a total failure. Take a piece of small diameter gas welding rod (3/32") for steel welding, or some other stiff, malleable wire, and turn a very short 90 degree bend in 1 end, < 1/8" long, and flatten/file the tip to a .020" thick flat. The idea is to make a go/no-go gauge that you can slip down through the hole by the pushrod, and has the 90 tip short enough that it can fit between the pushrod and lifter's retainer. (THAT is the trick...) Then see if you can slip the tip sideways and if it will go into the gap between retainer and piston. This will tell you if that preload is at least .020". This would need to be done on each lifter when the lifter is on the heel of the associated lobe and after then engine is warmed up.
If you know you have adequate preload, then the likely issue is a bad lifter or a bad lobe.
If the preload is not adequate, then it may some combination of thicker head gaskets, a low base circle on the new cam, height variations from standard on the new lifters, or pushrod or rocker wear. It maybe time for new pushrods.... in which case, you may as well as do the 273 rockers.
But that will be a waste of good $$ if the preload is good at this time, and all the problem is a bad new lifter. So IMHO take your choice: properly measure preload, or just bypass that question and do the new rockers with the risk that you still have a bad lifter or lobe.