Purple Shaft lifter issues?

Put the lifters in a lathe and run a dial indicator across the face to make sure it has .0015-.0022 taper/radius across it.

If they have that, use a good break in oil not some off the shelf oil with an additive. If you are running a double spring pull the inners out. They make a tool to pull the retainers off with the heads on. It’s cheap.

Make sure it fires off without a bunch of cranking. Make sure the carb is full of fuel, use a good, known ignition and make sure you prime the engine before start up.

Get it lit and keep the rpm at 2000-2500 for 20-25 minutes. You can change the rpm while it’s running. It doesn’t have to and shouldn’t stay at one rpm the whole time.

Pull the rockers and add the inner springs. Retorque the heads while your in there, regardless of what gasket you use.

Fire it back off and run another 20 or so minutes with the inners in. Then send it.

If you don’t have a double spring skip that part.