Cleaning, clearancing and mock-up:

Big block Chevrolet engines are sometimes known for having an appetite for flat tappet camshafts. Several factors can contribute to the issue such as improperly located lifter bores (the OEM's weren't always so accurate when it came to machining tolerances), and tight lifter bore clearances. Todays modern aggressive cams also tend to put the lobes closer to the edge of the lifters which can exacerbate the problem. As such, it's best not to get too carried away when it comes time to choose a cam.

As a matter of standard practice, I run a flex hone through the lifter bores just to help clean up any "boogers" that might be hiding inside, and to help remove any varnish that may have been left behind after the block was cleaned.

Since a stroker crank was destined for this engine, I needed to ensure there was enough clearance between the connecting rods and the bottom of the bores and the oil pan rails. While the oil pan rails cleared with room to spare, the rods were uncomfortably close to the bottom of the bores, although they did technically clear. The bores were marked where the interference potential was noted, and an hour or so spent with a carbide burr and a grinder left everything considerably more comfortable. Note that the relief was deburred to avoid damaging the piston skirts at BDC.

Tech tip: Whenever ANY non-original rods are used, it's a wise idea to check for sufficient rotating clearances.

Next up: Component selection, degreeing the cam, checking for valve-to-piston clearance and bearing clearances.