Thanks Louie L, I am using the stock starter bolts. The shoulder (part that the long starter bolt goes through that mounts to the block) on the lt4 starter - duralast PN 17124 has the exact same length as the stock starter. So I used my stock starter bolts.
The shoulder of the stock starter measures 3.6" the mini-starter including the LT1 starter has a 3.3" shoulder. The 3.3" shoulder could move the starter gear up, placing it closer to the apex of the flexplate. This could cause some clearance problems i.e the starter gear when engaged with the flexplate, you should have at least 0.035" between the crest of the starter gear tooth and the trough between two flexplate teeth. You should be able to stick a medium size paper clip in between. If it is too tight you should shim the starter down, this lowers the starter. Lowing the starter adds space between the teeth of the flexplate and the teeth of the starter gear. I swear I did not know this two days ago.
Anyway this afternoon I removed all the shims I had except for 1 1/16" shim. I measured 0.045" of clearance between the starter gear and flexplate when engaged. Then I went up to the front of the engine and rotated the motor kind of quickly,, and click!! the starter gear popped back of the flexplate back to its starting position. I think I am good.
The shoulder of the stock starter measures 3.6" the mini-starter including the LT1 starter has a 3.3" shoulder. The 3.3" shoulder could move the starter gear up, placing it closer to the apex of the flexplate. This could cause some clearance problems i.e the starter gear when engaged with the flexplate, you should have at least 0.035" between the crest of the starter gear tooth and the trough between two flexplate teeth. You should be able to stick a medium size paper clip in between. If it is too tight you should shim the starter down, this lowers the starter. Lowing the starter adds space between the teeth of the flexplate and the teeth of the starter gear. I swear I did not know this two days ago.
Anyway this afternoon I removed all the shims I had except for 1 1/16" shim. I measured 0.045" of clearance between the starter gear and flexplate when engaged. Then I went up to the front of the engine and rotated the motor kind of quickly,, and click!! the starter gear popped back of the flexplate back to its starting position. I think I am good.