I've been doing some reading and have found that the adjusting bolt on the rocker arms should show threads on the bottom with the correct pushrod length. This is where mine are with a correct length solid lifter and .001 clearance on the valve stem but they will go slightly lower when the preload is set on the new hyd. lifters. Is this OK or do I need to go a little shorter on the pushrod length.

iirc MP wanted 9/32" of ball/thread protruding under the rocker arm on those which likely is ~1&1/2 threads showing (mockup & see what you get). (1) Proper amt of threads showing (2) preload to ~.020" (3) proper length pushrods to achieve that. If the pushrods you have available give you more preload than that, run em & if you have a pump up problem then bite the bullet & order custom ones (I'd suggest Smith bros)

Thanks for the info, I'll check the length below the rocker arm tomorrow and I only have about 2 1/2 threads above the rocker arm now. My pushrods are ready to trim to length and insert the cups and I want to get it right the first time.

You know the old saying measure twice and cut once.

Thanks

I had a set of those MP cut to length pushrods once. It's the threads/distance below the rocker arm that counts as there's a squirt hole in the rocker arm under the arm that extends out & contacts the valve & the round nub/pushrod cup needs to be at the right distance so the squirt hits it and that the pushrod/threaded ball angle ain't too excessive at full lift and enough threads above the rocker to use the locknut & could mill the rocker face there thinner if needed. then you need the right preload. www.hughesengines.com has an orange sheet & has additional checks such as at 50 or 60% of cam lift (depends if SB or BB) that when viewed from the end of the eng front or rear that the pushrod/rocker are at a right angle at that lift percentage. Then there is the wipe pattern on the valve stem tip which is more a function of the height of the (5) pedestals & you can raise the shaft with shims and mill the notches deeper to go the other way & sometimes the rocker arm that contacts the valve ain't long enough, then there's coil bind/retainer to seal/retainer to rocker clearances . Alot to check. Definitely buy or make an adjustable pushrod & mockup/check EVERYTHING & go from there. I would find the preload that YOU intend to go with & JBweld a junk hyd lifters' retainer solid at that height & use it for mockup checks

I think we are talking about two different rocker arms, these are the early solid lifter style which oil directly onto the adjuster screw just under the threads. The hole you can see in the picture on the end of the arm goes straight into the center of the rocker. What I have right now is about .350 of the adjuster showing below the rocker which is way more then 9/32" (.2925)
This style doesn't have a lock nut just interference threads to hold the adjuster in place.

We're talking about the same ones & yes you are correct that they oil (on that side) down thru the threads and the squirt hole I'm thinking of is on the other side for the valve stem tip (been 10 yrs since I last used that type). Alright, I would check cup to rocker clearance at full lift & Hughes' check of the right angle at 50 or 60% (I forget which) of lobe lift. Holler how it goes & what the solution end up being

I'll let you know in about a week when I can back to working on it.

Thanks again

Myself,
I'd ditch the whole setup, Why??? You will never get the rockers to clear the springs and retainers no matter how much you grind them, And they will not hold up to any reasonable spring pressure. No offense meant but a cheap valvetrain set up is not always good

If you are planning on using the original solid lifter pushrods with new hydraulic lifters, chances are very good that they will not work. The hydraulic lifter cups sit higher inside than the solid lifters. The OEM difference is at least 1/4"!

Comp Cams has some pushrods listed as being for hydraulic lifters, but they are about 1/2 way in between the two measurements (7.5" for solid and 7.2"+ for hydraulic) and tend to be a bit too long as well.

If it's in the budget, a comparable set of beehive springs can solve any clearance issues with the rocker arms.

Clearance isn't an issue on the springs just the length of all the stock pushrods with a squared block and milled heads.

P.S. Summits G6420 pushrods listed at 7.234 overall length actually measure 7.388 from ball to top of cup.