Yes, different cables and different throttle brackets.

All good info, thanks for the tips. I have a 68 350 that came with a 2 barrel. I'm wondering if there was a difference between two and four barrel cables and/or pedal assy. The previous owner put in a different 350 with a quadrajet and when I bought it, he said it never did make a whole bunch of power. Found with the pedal to the floor, it just fell short of starting to open the secondaries. Might be something to check.

looking for a 5 speed to replace my T-10 transmission

Thanks for these additional perspectives. I've rebuilt my Rochester 4BBL and eliminated the restrictor flange on the secondaries and rebuilt my stock throttle linkage to remove the play, so I can eliminate these two factors.

Remaining factors are: a. the plastic bushing on the firewall bracket is worn and has flex, and b. the accelerator pedal which I cannot adjust (may be welded in place!). I'll replace both the firewall bushing and the accelerator assembly to try and get to closure.

FWIW I have seem a few aluminum accelerator assemblies that are more adjustable but $20 is a lot for a gas pedal and I do not want bling under my feet for a weekend driver. I will try the $60 assembly on Classic or Firebird Central (cannot find better quality).

Thanks Bob. Do you have strong opinion on the tradeoffs 65 vs. 60?:

225/60/R15 - sidewall height of 65 /146.5 aspect ratio (83.5" circumference)
225 /65/R15 - sidewall height of 60 /135 aspect ratio (80.5" circumference)

I want to get to lower the height of car a bit and squeeze in a meatier tire (which I was able to do on my 68').

Full disclosure that I am going into the 14x7 to 15x7 wheel upgrade to simplify finding tires to fit longer term.

Thanks.