292i6 carburetor problems

[292farmer]

ive got a 1972 c20 with the 292i6 and ever since ive got it about a month ago, it stumbles right after idle when press throttle and stumbles at higher rpms, me and my dad figured out it was the carb, we pulled it apart and the some idiot before had used some silicone? or some sticky gasket sealent that had actually spread into the jet and passages of the carb. we cleaned it out and it ran better but still ran lean, it runs perfect if we keep the chioke 3/4 on. we found the carb is off a a 1977 or later 292 and my dad remembers that those carbs ran leaner then those used on the early 70's so imwondering if any one know what size main jet were on the 77 and later monojet rochester mv and what size the 1972 main jets were? i cant afford a new carb so i want to increase the main jet to get it running smoother with out the choke on. it idles perfectly its just once it gets throttle it stumbles and runs lean, and yes i have replaced the fuel filter, and the pressure is 4psi after the fuel pump which im told is normal for i6. thank you for your help.

[Wrenchbender Ret]

Did you check the metering rod adjustment. When you hold the retainer down with the throttle closed the specks usually call for about 2/32 between the retainer & the body . Sometimes increasing it about 1/32 will ritchen it up. That has about the same effect as a larger jet. Make sure the metering rod is installed correctly on the retainer. also raising the float level a little can help.

[292farmer]

we raised and checked the float we did check the metering rod but will try increasing it some more to see if that helps thanks

[silverstreak]

One thing I would check just for giggles, is make sure the advance weights in the distributor are free and not sticking or binding.
I was doing some research on the Monojets when I was thinking of running 3 of them on my 63 250. However, I could not locate a source for jets so I went with some different carbs. Here's some info I can share with you though.
There were 3 different sizes of monojets, 160cfm (1 7/16 throttle bore) and 210 and 250 cfm (1 11/16 throttle bore). Monojets use different jets than the other Rochester carbs, they can be identified by 5 radial lines stamped opposite the jet number on the top face of the jet. The jet number is the orfice size (95=.095) Subtract 100 from the last 3 digits of the part number (7034154 = .054) Let me know what size jets you need and I can lookup the part number if you have a source for them. They range in size from .054 to .118.
The metering rods come in sizes from .070 to .098 which is stamped on the rod itself, however the part numbers don't correlate to the size. I have a list of those as well if you need them. The size is of diameter of the thicker portion of the rod that would be in the jet at high vacuum / idle.

[292farmer]

lol actually last nite me and dad went through the dist. and put new points in, i also made the idle mixture rich, which helped with the stumbling right after idle when i touch the gas, putting in a new coil in weekend., not that it mattered much this morning it was 22* out brr! truck wouldnt start..