Originally Posted by DoubleVision
One thing I noticed is the galley plug face is flat, just as they are on Vortec blocks. Even so your block is a non vortec, it still could be possible that it will require a vortec type chain. I went and took a look at the face of both my Vortec blocks and they're identical to yours. When I looked at a older 305 block the galley face had the classic high low arrangement. Not saying this will solve the issue, but thought it maybe worth saying.
I wonder if its worth it to see if my machinist has a timing chain for a vortec that I could mock up real quick to check. I have only seen older blocks, vortec blocks and my block and I would definitely agree that mine looks like the vortec one. Idk what GM did differently between the flat tappet, the pre vortec rollers and then the vortec rollers.
Thanks for the input guys. Sorry took me so long to get back to you Ive been swamped with school and work.