I have a '70 nova with a 350 with a 750 holly with mech 4bbl . the throttle does not open all the way. It has an adjustable bracket.

Sounds like it needs adjustment. :secret:

Some cars had a fixed throttle rod up until 1969, then they switched over to a cable system. If your cable reaches to the bracket that holds the back of the cable (the square block threads through the square hole and the two wings open up to hold it in place) then the cable is long enough. If your adjustable bracket is being pulled forward by stepping on the gas then it is not properly secured; or you have way, way too much return spring pressure (I know NHRA rules dictate two separate springs to pull the throttle closed but overall tension is measure in inch pounds. You should not need a five ton sling to pull the throttle open or you will wearing out the bushings in the throttle body). :confused:

I prefer a plate mounting system that uses all four mounting holes of the carb base to mount both the throttle cable and the throttle valve cable (TV), and in my case a throttle position sensor and place to mount the solenoids for NOS. By tying it down so it can not rotate using all four holes you get a uniform gasket seal and a structurally sturdy piece that will not rotate due to torsional forces. :thumbsup:

Big Dave

Ben have you had someone step on the pedal while you watch the travel? If the pedal travel stops before carb is wide open you have either to short of cable or improper mounting of the cable retainer. There were different cables for the 2 bbl, q jet and Holley set ups because the throttle arms are all in different places., so it may be just a cable change is needed.

I found the throttle cable streached. put a new one on and it goes full throttle.

or it could be that :D
cool; glad you got it fixed