I have a 91 s10 with the 4.3 and wanted to clarify a couple of things. The timing is based on the #1 cylinder, right? I just ask because there are two timing marks on the harmonic balancer, speaking of which, which mark should be used for timing? I plan to get the compression stroke up on #1 to verify which is the correct mark but I believe it to be the one which is to the left when looking at the two when there in the closest position to each other. just did a carb swap with an HEI dist. i just need to get the timing right now. i think that i need to reset the dist. because i might be off a couple teeth. of course in the middle of this swap gas went up to $4+ p/gal. thanks for any help given.

 

based on number 1 turn the engine to TDC on the number one cylinder and see which mark on the crank aligns with the pointer.