How much do you think a 72 coronet with a 318 could tow?

318 should pull 18ft trailer and car fine. Like stated before it will lack on the stop and go but once up to speed it will pull fine.

How much it will tow isn't the issue here. The suspension is! You will need to upgrade the springs or add airbags and air them up before you tow. You could also put weight distribution bars on it and you will be fine.

You will need to add a trans cooler also. This is a must.

I would go with the airbags and weight disrtibution bars plus a good cooler. That would look awesome pulling a dragcar to the track with.

The reason I say the airbags. My friend had a set on a S10. He went to Lowes and loaded up with a ton of retaining wall blocks. The rear only sank and inch or two. I wouldn't have believed it until he showed me. We counted the blocks and added the weight, just over a ton. I am not sure what system he had. I would think a set of dragbags would work the same.