Other than the obvious (binding), is there a good way to tell if the pushrod clearance to an aluminum head is insufficient?

My 3/8" pushrods look very close but there is no mark on them at all. The machining of the tunnel is rather crudely done from the Speedmaster factory, but I can't see any rub marks there either. On the other hand, will there be much visible wear since the area is well splash-lubricated?

Would the wear pattern on the valve tips tell me anything? My rockers are ductile-iron so they make a sliding motion anyway...
thanks.

Yes, when the engine runs crappy and you pull a valve cover and see the top half of a pushrod is missing

On a more serious note, its tedious but if you spin the pushrods between your fingers as the engine is rotated you'll feel them bind

Gee, thanks But I'd like to know before that happens.

read my edited post.

Also, "theoretically", they should be closest to the head at max lift.

I've never tried to spin them by hand - will they actually turn with fingertips, when there's a 430-440 lb valvespring pushing back on the rocker tip?

Depending on which heads your using will determine where the pushrods are closest to rubbing.
On the good harden pushrod they will be shiny were they rub if they are not bending to the pressures
I look for .010 or more room temp clearances with aluminum heads, .003 on iron heads with the valves closed

I use layout fluid to see where they are rubbing.

After I clearance the area I check it by sliding paper between the parts.

No they won't .

Agreed. My bad. I think I checked mine with paper.

Just give them alight coat of rattle can black and turn it over . Look for scratches. Then run it in good and pull them out and check again

You want to solve the issue BEFORE you run the engine - and get metal filings in the motor or have have to pull the heads to clearance them. Spend whatever time it takes before you bolt the heads on for good !!

It's already been together and run for an hour before I discovered I'd made a different major screwup (see the Valves, meet pistons thread) As mentioned, no evidence so far of pushrod contact. This is more for reassurance, now that I'm extra paranoid about checking everything!

I agree, it's a major PITA to remove and reinstall big-block heads in my A-body, mostly becausethe B-body headers are difficult to move out of the way of the bottom row of head bolts. So I will definitely check this clearance.

Incidentally, Manton Pushrods suggested if clearance were a problem that I could replace the 3/8 x .065 pushrods with 11/32 x .120. But that's $300 for a set. We will see.

Didn’t sound like he was having a major contact issue . Light rubbing won’t “lathe” the pr . But if he sees light contact he could use a tapered pr .