I've played around with the base timing and have settled on 12 degree BTDC. The motor really loves this setting as long as I keep the revs under 3500, (which is very easy since I have a 2.77 diff).
If I go over 3500 the motor starts pinging really bad. I'm running 302 heads and if all 302 heads have 57cc chambers, then my compression ratio is about 11.3 to 1, (according to Techfax article number 613 at http://www.acl.com.au
A few places on the web have suggested that the full advance should all be in by around 2600 RPM. Refer to http://franzh.home.texas.net/engine.html#One
). Also see Techfax article 905 at ACL. Another useful site is http://www.gasresearchpc.com.au/html/lpg_system.html
The cam I'm using is a 972227 grind by Comp Cams (Crane). See http://www.cranecams.com.au/ford7082.htm
for specs. It creates heaps of torque and has a lovely lumpy idle. I just love the sound of a Cleveland and the rock-n-roll of a shaker). The carb is an Impco 425 on a Performer manifold.