How do I know I'm on the base circle before putting the pushrod length checker in? Also, which cylinder is the number "1" cylinder on an LS1? Thanks in advance. I'm a real rookie when it comes to this. Just want to learn.

Shaun

 

#1 = drivers front

when the pushrod hits the lifter, and the lifter is snugged down on the cam, you are there. if you mean top dead center, then you can rotate the motor til the piston is at the top of its stroke...you can put your finger over the spark plug hole and feel when it changes from 'blow' to 'suck'

 

First, rotate the engine by hand. When you see the installed pushrod go up and then back down, you'll know your on the base circle when it's gone back down.

 

A simple way to be sure - if you're working with the intake valve, rotate the engine until the exhaust valve is fully open (or vice versa if you're doing the exhaust valve).

 

good stuff in here:

https://ls1tech.com/forums/generation-iii-internal-engine/327734-cam-guide.html