It is that way here too RK. You could get a random check on highway VS off road diesel (cops use a dipper to check color). The gas is part menthol. It is very hard to find straight regular gas.... but it is sold & refereed to as "white gas" at one station here by my work. It is more expensive.
I thought about timing too. Timing gear is set 4 degrees advance due to cam. The dist is manual. checked vacuum line... seems to be okay. Have not put a gun on it yet or check full operation of advance... I will do it this weekend.
DD: that 72 Dodge you have... she has some low miles. Pretty impressive she tows yer go-carts & keeps chuggin... good work horse.
Ken- octane is one of those things we ass-U-me should be correct... but kinda like the timing gun... we should question what is really going on.