Getting car dyno'ed : Questions

Set your timing at 12 or 14 to start with. Your AF ratio should be around a 12.8-13.4. It really just depends on what your engine likes though. They should allow you to tune between runs. Also, see if they have a pyrometer and bring some ice bags with you to cool the intake between runs. You want the intake to be the same temperature on each run, or you are tuning for nothing. Your GT-40 shouldn't heat up much between runs, but the ice can help regulate the temperate. You can also use some wet towels to lay on the intake and let a fan blow on it if you dont want to mess with the ice.

If you feel the tune is pretty much on, then do the first pull, see whats up...if you have o/2s in there, then the AF ratio should tell you something right off...12s-13s would be a nice number to see...if things look cool AF wise..i would tweak the timing some, move 4 degrees...see how both the AF and numbers respond...

i did 8 pulls in one hour....one base....5 up/down timing, once we found the best timing.took 2 more to try to sneak more from the FP....best power was timing at 14....FP from 42 to 38 netted 8 ponies more...i pay 85 an hr for tune time..he drives it, i turn the wrenchs...i basically let it rip back to back pulls...the car was running sweet when i brought it in...so it was kinda easy...had no issues to work thru...

you got AFRs so timing could be higher for you....the dyno guy should be of some help if he's a mustang guy, otherwise your on your own...some guys know jack about em...my dyno guy is more an import guys...so he let me do all the wrenching, which i prefer...

have fun....