Hey guys, just put my 83 back on the road after doing a cfi to carb conversion. I set timing to zero degrees tdc and its running great. What do you guys recommend I set my timing to? MSD distrib, vacuum advance, Edelbrock performer intake and 600 electric choke carb.

 

Most aftermarket carbed folks usually start at about 10* BTDC as a base, and adjust from there. I'm no expert on timing for a particular motor, but as I have learned for my 350 ...

You want to achieve optimally a total timing of about 34-36* all in by 3000 rpms. Your distributor will advance timing mechanically so much, and thus you change the initial timing up so that you can reach that goal. However, most distributors don't come assembled with the right springs and weights for the mechanical to advance enough to reach that, without having a very high initial timing set (which usually creates detonation at WOT).

So you set the timing at a starting point (like 10* BTDC), and make a WOT run - if no detonation, then bump it up to 12 and run WOT again - and keep adjusting up until you get pinging (spark knock or detonation) - then you set it back down to avoid that pinging at WOT.

So, in my case, I got as high as 16* BTDC on my setup, and I had pinging at WOT at 16. So I tried 15*BTDC and couldn't hear any pinging, so I settled at 14* BTDC. Detonation can occur without the human ear hearing it, that's why the extra 1 degree down adjustment, just to CYA.

For me, this resulted in a total timing of about 29 *BTDC at 3000 rpms. In order for me to attain the "magic" 34-36 numbers, I'll need slightly heavier weights and/or lighter springs installed on the mechanical advance inside the distributor - that way it can advance my timing farther and faster than it can currently. These parts are available most anywhere as a kit (Mr. gasket and many others make them). I just haven't gotten around to messing with it anymore myself.

Oh - if you have an old plain jane timing light, you can order a timing tape for your balancer for about $10 - it has marks well past the 10 on your timing tab so you can see higher timing numbers (like at the 3000 rpms) - you have to measure the diameter of your harmonic balancer to order the right tape.

If you have a dial timing light, your instructions will tell you how to read higher timing numbers. Basically, you run the 3000 rpms, and move the dial on the light until the balancer mark lines up with ZERO on your timing tab, and then look at the dial and it tells you the timing at that rpm level.

 

Thanks for the response! So basically, from where my timing is now, I can hit it with my timing gun and advance amply, until ping at WOT and adjust from there?