A friend of mine has a 390 in an old pickup and he wanted to cam it up. He bought a crane with I think around 220 duration at .050" and .494 lift. He also bought thin head gaskets to up the CR. I did the figuring, and it's at a shade over 9.6:1. Got it together and broke in and tried to set the timing. There only seems to be about 15 degrees of advance in the distributor. Is that about right? Vacuum advance doesn't work, so I'm just working with mechanical advance. Set base at 10 just to start, that's when I found the vacuum doesn't work. Base at 10 and full advance is about 25 degrees and it doesn't come all in till over 3000. Was trying to get up to around 35 degrees full advance, but if I set the base at 20 it's too much for it to crank. I just haven't had time to mess with it again. Anyone have any suggestions to get more total advance? Also need to recurve it to get it to come in sooner.

 

Something in the mechanical advance isn't right, you should get a lot more the 15 degrees.
Start with that problem first before trying to re-curve or other mods.

 

Ten 4 that's what I figured.

 

Hi,

You need to pop the top on the Dizzy and look at the number stamped into the Reluctor. Will look like 13L or 18L or xx. Take that number x2 and that approximately equals the total mechanical advance available. The strength of the 2 little coil springs determines how soon the mechanical comes in.

 

This. If you're getting only 15 degrees from the mechanical, there's something wrong.

 

I would check the dizzy for wear. Remans are around $50 last I checked.