Doug, Keith, Randy, and Royce, thank you for providing this technical guidance. I'm a hobbyist who's willingness to turn a wrench far exceeds my qualifications to do so. The good new is, my interest in high performance cars stimulates my desire to learn how to work on them. The bad news is, I all too often find that there is no such thing as a free education with on the job learning. I successfully adjusted valve lash on a 289 with solid lifters, after watching others do it. I never felt comfortable adjusting rocker arms for preload on an engine with hydraulic lifters, because none of my car guy buddies did it or showed me how.
Even though I could use a remote start switch to crank the engine, previous to asking for help, I decided to take out the spark plugs and spin the engine manually with a socket and ratchet on the harmonic balancer bolt. I did that because I thought it gave me more control on positioning the crank and cam shafts to determine when the lifters were on the heel of the cam. I removed the distributor because I thought that I needed to spin the oil pump to pump up the lifters. Now, if I understand your comments there is no need to pump up the lifters when I set rocker arm preload. And, I should adjust each rocker for zero lash and then add another 1/2 turn for preload. Zero lash is when the rocker arm adjuster applies enough pressure that spinning the push rod starts to become difficult.
Regarding why I'm using adjustable rocker arms...
In 1977, I needed to replace my original engine. I purchased a 428CJ that was pulled from a '69 Torino Cobra. I disassembled the engine and took the parts to Shaw's Speed Shop. The store's manager was more than willing, and I thought helpful, to make recommendations on how I should spend my money rebuilding the engine. Besides the typical procedures, i.e., hot tank cleaning, magnaflux, cam bearing insertion, bore and hone of the cylinders, I had the block decks paralleled and the block align bored.
When we talked about cam selection, I went with his recommendation for a Crane "Fireball" 34434 and hydraulic lifters. He also recommended that I replace the stock rocker arms with Crane adjustable rockers, with locking nuts, and the associated ball & cup push rods. After reading your comments, I was reminded of his reasons for going with adjustable rocker arms. So I feel better about his rationale for the recommendation.
The engine ran fine for a while but had a right side valve tap that I couldn't quiet even though I adjusted the loose rocker arms a couple of times. While checking the fluids after a day out on the road, I saw that my coolant and oil looked like a black and white milk shake.
That was back in the early '80s. I parked the car and pulled the engine, intending to rebuild it. Well, life events interfered and it wasn't until some 20+ years later later that I could do something about it. Incidentally, I was one of those guys that kept telling Domenic that the car wasn't for sale as I was intending to get to working it some day.
In 2007 I had a professional engine builder, Doug Meyers, rebuild my engine. He installed Crower cam 16243, the associated flat tappet hydraulic lifters, and push rods. He also reused my adjustable rocker arms.
Crower cam 16243, Grind #297HDP, is described as having:
Intake duration 297 degrees, Lift .590"
Exhaust duration 308 degrees, Lift .588"
Based on a 1.76 rocker arm ratio, Intake & Exhaust
The spec sheet doesn't provide an overlap spec, but provides information, "...for degreeing cam only. Correct only at 0.050" tappet lift.":
Intake opens at 10 degrees BTDC and closes at 46 degrees ABDC.
Exhaust opens at 57 degrees BBDC and closes at 5 degrees ATDC.
I can't really make hide nor hair of those specs, but I've included them in case they are important for this discussion.
The engine sat assembled on my engine stand until 2015 when I had my Shelby restored.
So, that's the whole story as to why I have adjustable rocker arms on an engine that uses an hydraulic flat tappet cam.
Any other tid bits of help you can provide will be greatly appreciated. I'd really like to get this engine running as it should, without having to pull it out.
Steve