I just bought a 73 1.7 and it was running fine the 2 hour drive back, and while dad and I were tuning the duel carbs the engine got stuck in full throttle. Anybody have experience with this or have any suggestions?

That is a CRAZY paint job... Nice looking car. I am an FI owner, so I can offer no carb help... with the exception of something got stuck in the pedal or the cable ???? no such thing as a vacuum leak for you.

Good luck

The throttle is controlled by a cable so all you have to work with is the pedal, cable through the center tunnel, and the carb linkage. Figure out which item is sticking and fix it. Have you tried disconnecting the cable from the carb linkage? This will help determine where the snag is.

One of the most common mistakes with these cars is to wrap the throttle cable around the clutch cable during installation.
Depending on how you drive, you might not figure it out right away.

So look for something interfering with the cable in the front.
I just did this yesterday.
I unhooked the cable at the carbs and hooked the cable in the engine compartment to the firewall with a spring I had laying around.
Then I crawled under the dash with a light and made sure the pedal mechanism and cable were free and moved freely.

If you have a pedal board, you would have to remove that first to really get a good look.

I also had a runaway throttle condition while firing it up.
Turned out to be a plug wire stuck between the throttle arm and the base.