After engine rebuild, I got about 500-600 miles out of it and it started to tick. I pulled intake and found out that 3 pushrods are bent.

In the process of rebuilding I swapped cam to B body LT1 cam (max lift .430) and put on Comp Cams roller tip SA 1.6 ratio rockers (mostly because I got these at fair price and they don't deflect as stamped stocks). I checked the pushrod clearance and they were really close to the hole edge, but they didn't rub if I turned the engine by hand.

The heads are ported 187 casting swirl ports, original rockers were SA type too. Heads have elongated slots for pushrods. All pushrods have shiny spots where they came out from heads so I guess they all rubbed, but I have read it's the fault of stock design (elongated narrow holes+SA rockers). The bent ones were slighlty shinier, so they might have caused binding. I guess that I have to pull the heads and machine the holes to be safe side?

Another question - most rocker swap threads say, that if one uses 1.6 ratio rockers then one should get slightly shorter pushrods to get the geometry right. I haven't found any place that sells shorter rods, all seem to be longer (like +.050 or .100 not - .050 or .100). When I checked the geometry, the rub mark was slightly off center to exhaust side. Some say, that it shouldn't matter where it is, I only should aim the wear mark to be as narrow as possible. How are your experiences, should I get shorter rods or just replace these bent ones with stocks and only modify the holes to loose the possibility of binding?

 

It could be possible they didn't bind by hand because the motor was still cold. After the heads get warmed up the clearances could have tightened.

Summit or Jegs should carry different lengths of pushrods. I've never heard of using shorter pushrods. I would think that would defeat the purpose of going to a 1.6 rocker that would have a longer fulcrum throw? Each setup will be different so just have to test it.

My setup is using 1.6s with a solid roller camshaft with normal lifters (not small base or extended body) and when I checked it the normal length pushrods had a good wear mark.

 

Did you check the retainer-guide clearance? 1.6's might have pushed your luck too far without machining.

 

I didn't check that, as I estimated that stock heads should be OK under .480 lift. I checked one valve that had bent pushrod and there's no evidence, that retainer had hit the valve guide.