Performance Q

The '81 is, by all accounts, the bastard child of the Spiders from a performance standpoint due to all the emissions stuff that was thrown on to the car. From what I've read, the '74's are probably the best performing of the bunch. My question is though, how does a '81 with all the emissions hardware removed compare to a '74? Just curious as when I bought my '81, all the emission stuff was removed. No air pump, EGR, or anything else. The only crappy thing still left on it is the monofarfalla intake. Would changing that out result in any noticeable performance increase or would it be a waste of time?

Thanks very much guys!