383 question

Go to Hughes Engines, they make their own rockers, hold downs and heavy wall rocker shafts, (not cheap) and have a very good written procedure to determine finished push rod length along with correct angle alignment, I'd stick with the 1.5's. They can explain it all. They will also assemble the push rods and send them to you after you use their solid lifter and adjustable pushrod to determine the correct length. Here's my latest installation. On a different subject, a converter with a higher stall 32-3400 RPM maybe in your future.

http://www.hughesengines.com/Index/index.php