X2 on the Canadian Pontiac blocks. Those blocks came with hydraulic lifters so you can use either sold or hydraulic lifter. Chevy 261 truck block, I have never seen one drilled for hydraulic lifters. That is not to say that none ever were, just that I have never seen one.
That being said, as you may know, the new manufactured hydraulic lifters have been problematic for quite a few years now. A nasty habit of collapsing within a limited number of miles. Really the only way to get the best shot out of using hydraulic lifters, at least in my opinion, is to scrounge for a GM NOS set, or a RNOS set that are at least 20-25 years or older post manufacture, preferably USA made.
On the mechanical lifter side, the current manufacture solid lifter does not struggle with quality issues so you can use new. Solids are pretty reliable, will not collapse, and do not suffer ticking from air in the oil, lifter or under the push rod seat. Yes, sounds a little bit like a sewing machine, but runs reliably and requires only a bit of maintenance in the form of a valve adjustment every once in a while.
Last edited by Dragsix; 05/21/2019 3:02 PM.
