questions about factory tune

[70chevrolet]

I am old school and I am not wicked knowledgeable with computer tuning. I had a few questions. I believe my car may have been tuned at some point and I want to restore it to factory specs. Specifically, the car idles as if it has a ton of intial timing. If my vehicle had a custom tune at some point, is there any way for me to reset it to factory specs without special equipment? Or, can I adjust the timing? If not, I am located in Mansfield Mass, is anyone out there that has a tuner and that would be willing to help me out with this for cash?

thanks.
mike
MRCHEVYVAN (at) GMAIL