In 1975 the carb was modified to include a pull over enrichment system which feeds extra fuel at high speeds,and air bleed
metering rods that enrich the mixture according to throttle opening.Otherwise same carb.easy to tell the difference by looking down
inside top and working throttle,on the 2150 you will see 2 small brass needles that raise verticle near the center.The 2100 you wont
see these parts or anything moving but lower throttle plates.
BTW do you know there are at least 2 sizes of these carbs? I dont know the difference but i had scraped up a older 2100 from i think
a 390 cu in and it had larger venturies and took a bigger base block (bigger holes) same outside.Also the ford spacer blocks are different
on different years (again i know not what years) but some are curved inward in the back and some are straight,same as carbs are.If you dont
use the ford alum. spacer block then it shouldnt be a problemi would think.Also i have seen factory jet sizes from #40-45-50-55 in different
21 model carbs.I have used 21 models on my Bronco,mustangs 80 and a 69 and i always liked the 2150 better,seemed response was
better and was better on gas
Thanks for the input folks. This isn't some hard core rock-crawler or die hard trail jeep. Just my wife's daily driver and I want something with a little more oompf, a tad more reliability, and a boat load better fuel economy (QT w/auto. 9.5mpg. maybe.)
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