Carbs

[N PRGRES]

While my goal is to FI my motor, it's not goiing to happen this year as I have other things I want/need to do first.  The carb on it now was "modified" for racing by a previous owner and while we have done about everything to make it right, it just isn't cutting it.  So, I am going to begin to look for a new carb to put on it. 

What are the differences in the years of the carbs?  So my motor is a 73 400 in an 81 TA, it has the correct shaker and plate so we don't need to go through that, I just don't know much about carbs and what would or would not work.

[firebirdparts]

Well, I assume here we're talking about quadrajets.  The shaker will fit them.  All GM cars had a unique carb calibration.  They're all 'different' in jets despite being the same size.  They were all very similar externally; in terms of internals and all that, they added an adjustable power valve in 1975, but what you really want to know about is shape factors.  The fuel line comes in the front on a Pontiac and you can easily see that.  You probably want a choke similar to what you have now.  You also might run into some trouble with the throttle linkage.

That argues I think for another Pontiac carb off a mid to late 70's not-expensive-not-collectors-item application.  Even the 301 carbs had big venturis for what it's worth.  If you find one from the earlier 70's that is cheap then that's great.