[PeteKz]

I'm aware of the TPR too. I'm pretty sure my original 1973.5 CIS engine had one.

What I'm looking for is a WUR/CPR that enriches under load (low vacuum), and leans out at cruise, which is what later electronic fuel injection systems do. Since I installed my AFR a month ago, I watch it regularly when I cruise or accelerate. I have noticed that the WUR gives roughly the opposite of the behavior I expect most of the time. When I put my foot down, first it goes lean before enriching, and then only a little bit.

To give some actual examples: Last night I was cruising on the I-5, and noting the AFRs, because I'm going to swap to the 033 today or tomorrow, and run the same loop, and compare the behavior. The AFR was in the low 14 range at cruise between 60 and 80 MPH. When I accelerated, it would jump up to the 15+ range for a second or so, then drop back to the mid 14 range. When I took my foot off the gas, the AFR would drop to the high12 range briefly, then rise to the mid-13 range, then gradually up into the 14 range as the car slowed down. Yes, the hoses are hooked up correctly, and the thermo switch is open after 10 seconds of warmup, etc.

Add to the puzzle: At idle, fully warmed up, it's showing about 13:1, which is much richer than I expect.

Whereas, what I expect to happen is that it should be cruising at mid 15 or a bit higher, and when I accelerate, it should drop into the high 12 range. When I back off the throttle, it should rise to the 15-16 range, and when I return to cruise, it should stabilize in the low to mid 15 range. And I expect it to idle in the high 14 to 15 range.

Anyway, I'll continue to play with it and post my results here. I also need to fiddle with the CO screw some more and see what results I get after re-setting the idle AFR to 14.5 or so ( I did previously set it to that value)