EQ mag headed 360 with hyd #718041-09 .521/.512 Howards cam. will be raced only. If my preload on mockup is .030" and I with clay or dial indicator check P/V clearance with an adjustable solid lifter like the one Hughes sells/rents (1) should I (A) lock the cup at .030" down from the snap ring & check it or (B) lock it just under the snap ring? (2) should I use the pushrod that gave me .030" preload? I may as need get different pushrods. (3) ~6200 max RPM and I have 2 sets of springs 142/308 and 142/312 lbs to choose from (closed/open), which do you suggest (they are close). My shop wants .080/.100 P/V clearance but I am severely stuck on the procedure. Thank you for your time.

adjustable solid lifter??? because a hydraulic lifter would bleed during the procedure, i would use a solid lifter to check the p/v clearance. with an adjustable pushrod or an adjustable rocker. set that valve at zero lash then you can take measurements of your piston to valve clearance. that would be with clay. otherwise, you can use a checking spring and measure at different positions of the crank directly by pushing down on the retainer and measuring from the retainer with a dial indicator. this would be more accurate than clay and it is how i do it.

with a checking spring you could use a hydraulic lifter. to directly answer your question, i doubt that lifter preload has a big effect on p/v clearance. in doubt, check it at both zero lash and then with .030 preload.

My bad, an adjustable HYD lifter like Hughes has (that can be locked solid at different cup heights (to match the preload). OK, if I have enough clearance with it checked with the cup locked just under the snap ring will I be OK? I would think I would be OK unless things actually "seperated" floated? (if that is possible) but for sure I have been sweating bullets over this! (& the geometry issue).

I would check it with checking springs and a solid lifter first I have ran as little as .030(accidently ) on the intake valve to piston, you have to check all eight of them also and as little as .050 on the exhausts. I had mock that engine up and every thing was good at the beginning of the season, half way through that year I removed the heads and had them cut down from 86.0 CC to the legal 81.5 CC NHRA spec. that stupid car didn't run any different with that change
I found the close valves to pistons clearances when I tore that motor down the next time Ended up that I had some longer stock rods and some shorter ones I was lucky that I didn't break any parts on that deal
Check, check and check again, especially on race motors

Cab I have some solids/adjustable pushrod checkers/light springs but would the slightly different "angle" give me a false reading or is that a moot point?

I think the angle change will either increase or decrease the V to P clearances by a very small amount(.001 to ,maybe .003), probably not enough to worry about

that's good to hear! thanks Cab. I will get after it