m in sc
New member
So, as the title suggests, i have modded my 250 to take an autolite 2v carb. (milled log to fit, no restrictive adapter) I'm lucky, and have 2 to use, one is off a 67 289, the other is from a (fairlane?) 260 V8. Both have been rebuilt and ultrasonically cleaned correctly ( by me)
I initially ran the 1.01 carb, and while it ran great, it also ran rich. as hell. made lots of power when the throttle was opened but idles rich, and just seemed to be dumping fuel. the carb is in great condition, the emulsion tubes are not cracked, etc. but I could NOT get it to lean down any at idle. checked float level, etc.
the other carb i put on out of somewhat desperation, also in perfect shape, and decided to try it but the caveat was the interchangeability of the jets with Holley ones, which are on the shelf at the local speed shop.
for clarity: motor is a 76 250, bottom end dead stock, shaved head ).070 some porting, comp cams 260H grind cam installed straight up, HEI ignition and 6-1 header.
so, the 289 carb had 54 mains, and i am truly unfamiliar with the emulsion setup on these, so not sure whats in there, aside from its stock. The other (260) one had 46 mains, and the rest stock. I feel liek im leaving a bit of meat on the bone with the 0.98 carb, but i did have to jet it up to Holley 50 mains to get the lean detonation out of the motor. going to jet up to 52's and try to dial it in even more. Motors running nice and in range with these, temp wise as well, sitting around 190-195 (prior it would climb to 208-ish on the highway at 2800-3k rpm)
my concern is more with mid-range. I figure, on the emulsion/spray assembly in the carb, there are 2 drilled orifices on the top of it that allow air to emulsify into the assembly. I speculate i can drill and tap these holes and use air jets to control the richness of the cab in this circuit.
who is familiar with this modification on the autolites, and any advice would be great. I also speculate i can do the reverse for the 1.01 and maybe lean it out a a bit to make it work if i need to. The carbs are close in size so i'm not opposed to leaving the .098 on.
also, i know the spray assemblies can PHYSICALLY be swapped, but didnt know about the pitfalls of doing so.
I know thats a lot, but im def curious as to how these can be tuned. Thanks.
I initially ran the 1.01 carb, and while it ran great, it also ran rich. as hell. made lots of power when the throttle was opened but idles rich, and just seemed to be dumping fuel. the carb is in great condition, the emulsion tubes are not cracked, etc. but I could NOT get it to lean down any at idle. checked float level, etc.
the other carb i put on out of somewhat desperation, also in perfect shape, and decided to try it but the caveat was the interchangeability of the jets with Holley ones, which are on the shelf at the local speed shop.
for clarity: motor is a 76 250, bottom end dead stock, shaved head ).070 some porting, comp cams 260H grind cam installed straight up, HEI ignition and 6-1 header.
so, the 289 carb had 54 mains, and i am truly unfamiliar with the emulsion setup on these, so not sure whats in there, aside from its stock. The other (260) one had 46 mains, and the rest stock. I feel liek im leaving a bit of meat on the bone with the 0.98 carb, but i did have to jet it up to Holley 50 mains to get the lean detonation out of the motor. going to jet up to 52's and try to dial it in even more. Motors running nice and in range with these, temp wise as well, sitting around 190-195 (prior it would climb to 208-ish on the highway at 2800-3k rpm)
my concern is more with mid-range. I figure, on the emulsion/spray assembly in the carb, there are 2 drilled orifices on the top of it that allow air to emulsify into the assembly. I speculate i can drill and tap these holes and use air jets to control the richness of the cab in this circuit.
who is familiar with this modification on the autolites, and any advice would be great. I also speculate i can do the reverse for the 1.01 and maybe lean it out a a bit to make it work if i need to. The carbs are close in size so i'm not opposed to leaving the .098 on.
also, i know the spray assemblies can PHYSICALLY be swapped, but didnt know about the pitfalls of doing so.
I know thats a lot, but im def curious as to how these can be tuned. Thanks.