another stupid timing question

[jamiebarnesjr3]

i just got my sbc 355 dropped in my truck.but somethings not right with timing which for some reason is the hardest thing for me to get right everytime i usually tinker till its good enough but this is a 2500 engine and i want everything perfect. what i have is a standard chevy 350 bored 30 over with flat top pistons,edelbrock performer rpm cam, headers with duals straight out the back,edelbrock performer rpm intake,1.5 aluminum rollers, brand new hei dizzy,8.8 plug wires,and toped off with a 600 cfm holley single feed carb. the driveline in case it matters consist of a th350 with 2500 stall,and posi 3.42 gears. problem im having is the engine has the wrong timing tab on so im gonna pt timing tape on it and i dont know how to properly install it. second is ive got all the initial timing set with #1 tdc an all that. but what do i do once i get the tape what should the total timing be at what rpm? do i do total timing with vaccuum advanced pluged in or not? any help would be greatly appreicisted. also the carb was " played" with so what should i set the screws at as a base point. thanx in advance.

[Captkaos]

timing tape install:
http://www.jegs.com/InstallationInstructions/100/121/121-8985.pdf

you need to set you base timing not total, vaccuum disconnected.

I would start the Carb with 1.5 turns of seat.

[jamiebarnesjr3]

thanx capt im goin out to put tape on any idea of base timing

[screamin86]

What heads are on it and what compression ratio are you running? When I first started my 350 I started out at 11deg and worked my way up from there.

[78silver]

This is a good question, I have the same problem.  Information in a pdf on Speedway motors.com indicates sbc motors used harmonic balancers with a timing mark 2 degrees left of the keyway before 1969, 10 degrees left of the keyway from 1969-85, and 40 degrees left of the keyway from 1986-91/92.  If you are using a bolt on timing tab located at about 1:30 to 2:00 you need a balancer with a 0 degree mark about 10 degrees left of the keyway.  Most aftermarket balancers have their mark 10 degrees left of the keyway.  A picture of Summit's SUM-161350 shows the relationship of the timing mark and keyway typical for 10 degree left balancer.  These numbers appear to me to be approximate.  I would not use them with a timing tape to relocate a timing mark on a 40 degree left balancer to time to a bolt on tab meant for a 10 degree left balancer.  Best solution, without accurate measurements, would be to replace the harmonic balancer with one meant for the timing tab you are using.  If anyone knows better numbers or has actually measured them, I'd appreciate seeing them posted.