vacuum advance issues

[crazy longhorn]

Originally Posted by Erratic67

Thanks for the additional input .... If you begin from the start of this post you will understand issues I was having in the begining and now current. Trying to decifer fleetside is way over my head at this point. Thanks to storm, I have gained a lot of ground and very much appreciate.
1. Yes timing was set with vacuum advance disconnected and remains that way.
2. Pick up coil was tested and proven to be fine.
3. My tach. is not working correctly so total was set at 35* when the mark on the harmonic balance stopped rising when excellerated, "RPM was unknown"
4. I didn't check total when originally at 8 BTDC, which may have stopped the backfiring if I would have set the total @ 35* then.
5. If i choose to decrease initial back to 8 then reset total back to 35*, what will that hurt & do I need to find TDC all over again?

What Fleetside was saying, is that the curve on the dist is not ideal. You can recurve the dist, to get that 12-14 initial....best use stock weights/aftermarket springs. I like a Crane adjustable canister/spring set, & look for weights from a 3/4 or 1 ton truck (bone yard parts). You will tune the vac can last, & they all tune just a little differenty , according to gears/cams, ect. So I will try to be basic....IF, you say that she runs best with 35 on the total, that is where you should be! On that HEI, even with the "preferred" weights/centerplate, you will have 14-16 degrees initial, to hit that 35 total. use the spring combo that will let the curve "all in" @ 3000 rpms (2800-3200), & limit the vac can to 8 -10 degrees at the crank shaft. You should be in the ballpark. Any ?, ask as you play Longhorn