I have updated my web site with a full update on this project.
Jeep Forum thread on this project is here
So this is what we started with, AMC ignition box and computer are gone, MSD box has replaced it with the stock distributor and coil. So basically a stock set up.
This 32/36 was purchased with the the O.E. air filter ADAPTOR 99010.600 so that the stock air filter could be used.
Here they are side by side, note the throttle linkage is different and the 38 has studs for the Weber air filter. Also note the straight mechanical linkage on the 38. The expert that is guiding me installed .50MM Idle Jets, 1.45 MM Main Jets, 1.70 MM Air Corrector Jets, f7 Emulsion tubes, Vitro tip need valve.
Swapping the throttle linkage was very simple as I had followed the instruction when it was installed so it came apart very easily
Next was the studs on the new 38. they had to be removed and the holes drilled and taped to accept the larger bolts for the air filter adapter. Again not a big thing so long as you have the correct metric tap.
The next difference was there is only one vacuum port on the 38 while the 32/36 has two. One is delayed vacuum (not ported) and the other is not and was used for the vacuum to control the functions on the charcoal vapor canister. Again not a big thing I will just pick up the vacuum from the intake manifold for this purpose.
Also note that the fuel inlet on the 38 is on the opposite side of the 32/36. A new fuel line will have to be made up.
Next problem was the bracket for the throttle cable linkage would not sit down on the base because the barrel of the carburetor is bigger. A little grinding solved that problem.
Ok, so I "T" into the vacuum for the air filter to supply vacuum to the charcoal vapor canister, and you can see the new fuel line.
Test drove it with out any adjustments and it stalls at stop signs. Seems to rev better, but did not take it up on the expressway to check power above 45. Acceleration is not smooth, seems doggy in lower rpm then bogs down then picks up and goes pretty good.
With out adjustments I seem to have the opposite of what I had, with the 32/36, it was good on the lower end with lots of torque, but dead on the upper end, now with the 38/38 it stalls in the lower end, doggy down low but seems to pick up in the upper end.
I have been properly scolded for not adjusting it before test drive.
I spent some time adjusting.
I found that I could turn the idle speed screw in a 1/4 turn more before the vacuum registered on the delayed port. This allowed me to get the Jeep to idle without having to hold the peddle.
I checked the timing and found that it was at a static 6 degrees, bumped it up to 8 and then had to reduce the idle speed screw by almost a half turn to get the idle down to 500. There is zero vacuum at the delay port and I can screw the idle speed screw out and 1/8 of a turn before vacuum is registered on the gauge. So the idle screw is now 1/8 in before vacuum registers (every expert makes a big point on this).
INTERESTING point, the delayed port only develops 15 pounds of vacuum, while the manifold vacuum is close to 20. I'm wondering if I am getting full vacuum advance with the reduced vacuum for the delay port on the carburetor.
The 38 has adjustable low speed jets (32/36 does not), they were bench set at 1 1/2 turns, with an tachometer I found the "Best Lean Idle" by bracketing the fall off of RPM to be 1 1/4 turns out.
Test drove again, it does not stall, pulls pretty go, but not great, there is a small weak spot at about 1/3 throttle, seems to pull pretty good in the upper RPM 2,000 to 3,000 range. I am out of time and will have to try the highway tomorrow.
When I got back I added an additional 2 degrees in timing, now at 10.
Maybe this will remove the weak spot at 1/3 throttle????