Many of the Lincoln 460s used Rochester Quadrajet carbs, those manifolds would be spreadbore like you need. If you want a spreadbore carb, I would highly recommend the Q-jet over the Thermoquad. The phonelic (sp?) body of the T-quad warped and leaked a lot.
The 74 California 460s used a Carter Thermoquad which is a little different bolt pattern than a Quadrajet. The only 385 series engines I ever saw with a Q-jet were the 429CJ engines in the Torinos and Montegos. They were iron manifolds. I have one of the CA spec TQs, it showed up in my shop one day and the guy who had it wanted $25 for it, I still have it. Good luck on an intake.
I think from what I remember that the 4300D, TQ and Qjet were all just a little bit different. I believe the 4300D and TQ bolt patterns were the same, but the bore spacing/ locations and size were different. Best bet would be to see if you can find mounting gaskets for the two and match them.
Thermoquads and Quadrajets share the same bolt pattern, but not the same base gasket, the Thermoquad is unique in its base gasket, and you will have a vacuum leak if you use a q-jet gasket on the tq. The tq is a great carb when working properly, producing good fuel mileage and torque without sacrificing top end power when you want it.