Consider what happens when the main body is installed backwards. The back throttles do not move when you step on the gas. So the low-speed is stalled at whatever the secondary cracking screw has been set to.
When you step on the gas, the front throttles open, but there are no transfer slots, and all the fuel would have to come from the way too big secondary MJs, and the 4-corner idle if you got such. Of course the MJs are not gonna flow until the airspeed gets up. That it idles at all is kindof a testament to the rebuilder, who, it seems, got the throttles set set pretty close,lol.
The 292 cam needs quite a bit of bypass-air, and you got it! by having the body on backwards, any adjustment of the curb-idle screw, is principally adjusting bypass air. After you get it assembled right, and the transfer slot exposure set to taller than wide. and the bypass-air figured out, you will be able to reduce your idle-speed by retarding the timing some.
As to timing;
You have several systems on line at any one time.
1) The principal one is the power-timing. This is usually set between 32 to 36* with it being all in by 3000 to 3600, depending. The better your combustion chamber, the less advance it needs.
2) next is; idle-timing. Guys like to set it between 16* to as much as 25* with a big cam and a hi-stall TC.
A for me,I let the transfer slot exposure determine it. I ran the 292/292/108 at 14/16.. The more you give it, the more you gotta close the throttles to keep the rpm down. And then the low-speed fueling takes a dump. The slower you idle it, while maintaining the exposure, the more wicked that cam will sound. I had a manual trans so could idle it anywhere I wanted to, just be playing with the idle-timing. That 292 would go down to 600 without too much bother. She was not keen to stay running at 550, nor was I interested in running it that slow, but she sounded pretty good down there.
3) next is rate of advance, controlled by the flyweights and springs.
These three together, control your WOT timing, and Idle-timing, and I call that your Base-Timing. At all other times, your timing will be dead wrong. So,
4) for Part Throttle timing, the Vacuum Advance brings it's tune to the party
5) and that just leaves your Cruise Timing. Depending on your cruise rpm, the timing will want to be between about 42 to 56 degrees. If you don't provide what she wants, the fuel economy will suffer. With the right timing, you can take fuel out. which is a big deal with the 292.Cuz it will suck gas big-time, until you get it figured out. But Ima thinking that if you cared about fuel consumption,you would not have installed a 292 cam,lol.
Good luck
