I have a 67' 400 /4-speed. Stock set up, no headers. Still have the original throttle linkage and gas pedal set up, linked to original Rochester 4BBL (which installed an electric choke on). I am considering replacing the worn out linkage and pedal set up with a OER linkage or cable system. Strong opinions of which way to go and with what aftermarket products? My sense is that the cable set up will perform a bitter better but I do not want to waste money if not beneficial or necessary. Thanks.

Its always beneficial to replace something that is warn out. When these 67 throttle linkages are old and warn out they could jam up with the carburetor stuck wide open. I have rebuilt the bracket on the firewall with bronze bushings and fixed all the wallowed out holes in the linkage and then everything works fine.
If you want to go the cable route you need to get the cable and the cable mounting bracket on the intake manifold and the pedal for 68 and later.
its all just time and money

Thanks for your response /input. I did in fact rebuilt the stock linkage and tried to unsuccessfully to adjust the pedal height (as I have limited clearance between pedal and floor pan). I discovered that I was utilizing just 60% of my horsepower as I did not have enough tension in the linkage or clearance between pedal and floor! My hunch is that I am still utilizing just 85% of horsepower (due to lack of pedal clearance). Thus why I now considering replacing the pedal set up or converting to the cable system. Either approach could solve for me not being able to access full power but I agree that the cable conversion will be a bit more expensive and time consuming.

Even with the throttle cable i had to tweak my pedal for full travel. I actually cut it and re welded the whole thing and added some extra bracing so it would not flex and bend.

After breaking too many of the '68 cable throttles, I actually went and backfitted the '67 throttle. The rod linkage just seems much more sturdy and dependable. I didn't have to modify anything but that set-up came off a '67 400HO car. Maybe it was a bit different?

Can you recommend a well made /adjustable aftermarket pedal set up to use with my stock 67' throttle linkage? Given that I've already rebuilt the throttle linkage it will be fastest and less costly just to adjust the pedal clearance. Thanks.

This one is adjustable. It requires converting to the cable system.LOKAR throttle pedal assembly

Have you considered modifying the rod linkage? It seems to me length of the carb rod and the lever Throttle arm lever can be changed for better travel and geometry.

I read that some Firebird carb linkages were intentionally made so they would not open all the way. GM was afraid the Firebird would infringe on their darling GTO. They had the same exact engines, but were restricted from making the same power. What I don't know is exactly how they did it. Your problem may be that restriction.

I have worked on many vehicles with that Locar pedal. I was never aware that they charged that much for a total piece of dog doo doo.
They are just a cheap design thats made poorly and has as much slop as as worn out factory pedal. You would be better off fixing the factory firebird pedal.
They restricted the amount the secondaries opened on the Q jet. Thats how they did that.

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).

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.

Yes, different cables and different throttle brackets.