The tires in the rear are 235/60/15 ,Yes i believe they should be 14 inch, but does that make 30 mph difference?
I am not 100 % sure the trans is original, I know the motor is a 73 built, The trans has had a b&M shift kit with a rachet shifter ,3200 stall,rear end is 4:11 posi

So what are the simple steps????? Or could it be a bunch of problems?

Thanks Greg