With the T56 3.42 hears I run a nice 1500rpm at about 73mph the car runs pretty smooth just seems to be really hard on gas maybe 12-15mpg at best. My distributor (70's style h.e.i. has a highoutput coil, advance kit, stock vacume canister, accel wires) I have no clue what the timing is set at right now and I need to drive to Chicago tommorrow. I know an adjustable vacume can would help I can't get one of them in this little town tho.. Is there anything I can do without a timing gun? I don't have a timing tab or a gun and I really dont care about peak HP at this moment, I just wanna get some better mileage for the trip. Thanks, Benjamin

 

Without a timing light or tab, abt all you do is adv the timing until it pings under load, then back up the timing till it stops pinging.

You may find that the eng will kick back aginst the starter if the timing is too far advanced. On my old eng, that would happen before I got any pinging.

I'm assuming that you are running a carb. You could re-jet it, but that takes time to get right, and I wouldn't do it right before a long trip.

If you have an EGR valve, you'll want to check that it's working right. A properly working EGR will allow more ign timing (better economy) during cruise.

 

Something I always like to have hooked up to my car all the time is a vacuum gauge so I know what the engine is doing at various conditions.

Have you checked your car for vacuum leaks in any hoses? Check your air filter too.