as title suggests... I have a 250 six maverick with an autolite 2v conversion. However, I currently have a 0.98 dia carb on it. I have a 1.01 I want to use but would like a base on suggestion on main jets if anybody has any experience with this particular set up. just a rough range to start. mods include: 264 comp cam 6-1 header and 2.5 exhaust all the way out milled head hei ignition mild ported head it runs pretty good with the .98, but ran better with the 1.01 but was too wayy rich. I want to revisit this but have limited ford specific jets (the .98 autolite uses holley jets) If anybody can help, Thanks!
A 1.01 carb is for a small block 260(discontinued after '64) so should be very close on a 250... Assuming carb has orig jets and float height is correct, it should not be too rich... The .98 were used on the 221... Must be a late carb, generally through '63 the jets were same size as Holley though it is said the thread pitch was slightly different...
the .98...it is an early 221 carb and i had to jet it up with holley jets, im on 50's now. seems to be ok, but the 1.01 is from ? my buddy got the 1.01 on his 66 comet with a 289, its def a later one and takes autolite jets. so i dont trust the jetting at all, as i agree, it was off a 260 somebody tried to make work on his 289 i was thinking 45's ish on the 1.01. the .98 has been workign for over a year but i know theres more meat on the bone thanks for the help
The '63 289 used a 1.02 carb, during '64 they switched to a 1.14, late 289 and probably all 302 used a 1.08... The 1.08 should be easy to locate, with your mods it'd be what I would try... On the 1.01, it isn't but very slightly larger than the .98, maybe use one or two size large than the .98 but that's all it should need... As far a jetting for size of engine, most of time isn't really necessary... A carb is nothing but a siphon device, more air flow pulls more fuel, ratio stays somewhat consistent... A too small carb will often be rich at WOT as there is so much venturi action it starts pulling raw fuel vs atomizing the fuel... Also a too large carb is often lean as there isn't enough air velocity through the venturi to pull fuel from the boosters... In this instance a larger jet will probably help...
according to everything I have read, the 1.01 flows 40+ more cfm. like said, whats been done to the carb that was on my buddys 289 prior to him/me getting it is unknown, and im pretty sure its NOT the original that came on the car. (its now rocking a 4bbl and some other goodies but that doesn't matter) the venturies are a LOT different between the 2. like said, I had this 1.01 on the car prior but was too rich (it had some huge jets in it, some where in the 50's). when it was over 1500 rpm and the cam came into play it really ran well. it actually ran well down low but was just getting too much fuel. I always planned on getting back to the bigger carb but needed to get the motor assembled and used the .98 because holley jets were readily available. I have to disagree jetting wont matter that much, I dialed in that smaller carb best I could but I think its restrictive. I just ordered 42, 44, 46 mains from carbs unlimited. at 10 bucks a pair not bad. about on par with my motorcycle jets, I have hundreds of those. too bad they wont fit.... I was just looking for base line if somebody HAD a setup like this so I could get a starting point. this is my motor with the .98 on it
Kewl... I didn't mean jet should never require a change, but usually it isn't necessary... I ran a 4100 from a '65 A code Mustang on my stock '64 390 Galaxie and other than a couple rebuilds never touched it... It gave better gas milage and more power than the orig that had more CFM, the 390 could yank the secondaries open at 2500 RPM almost like they were mechanical... The large 4100 never opened till engine was past 4000 and if you know old bread and butter 390s, valve float hit as soon as it crossed 5K... If it would have spun to 6K the larger carb may have had the edge... I double checked my sources and originally the big jet 1.01 used between #41 & #44 jets... The small jet versions had between #45 & #48... The 221 carb used between #43 & #45, all those are small jet... Note the jet size varied by booster and/or application, the big jet 1.01 used either H, CA or CD, this should be stamped on booster... If you have the original number, I should be able to give you the factory jet size and booster numbers...
thanks for all the input, it IS appreciated. kind of verified what I thought jetting wise. it has like 52" in there now. Spoke with guy I got carb from today and he verified it was super rich on his 289 as well, so I think im in the right direction. will follow up with results on this as soon as the jets arrive and I can swap em.
Ok, so memory is a tricky thing. Turns out the bigger carb I had was not a 1.01, but a 1.14 with 50 jets. :/ so I figured id try it again. I rechecked a few things and found out the float level was a tad too high, so corrected that on the 1.14. tried the 46 mains, was ok but had a slight stumble off idle and surged at 1/8 throttle steady. but power was immediately better over the 0.98. so since im lacking 48's I put the 50's in, ( I did have asset of 52's as well from who knows where). drove th ecar to work today, seems to be spot on. but maybe a *hair* rich . not sure. however the mains did affect the low throttle quite a bit. (i'm more familiar with tuning motorcycle carbs so its unusual for a main jet to affect part throttle from what im normally used to). Another thing I found was the original mixture screws on the 1.14 had some scarring on them, so I pillaged th egood ones from the old 0.98 as they were in much better shape. remember, I took the 1.14 off a few years ago due to a rich condition, probably at idle with the float and fuel screws being th eculprit, not the jets (shame on me). However I was in the midst of a motor break in so a lot of carb details were fuzzy. I have 48's on order, need to check plugs and see whats up but id say its almost perfect. will roast the tire off the rim in 1st pretty good. but most importantly, drivability is greatly improved over the 0.98. which would probably be ok on the 200 I have in my other car a 62 falcon. (already have a weber on there so not going to happen)
At least you have a memory, I've forgotten what that was like... The 1.14 ranged in jet size from 48 to 50, all large type... The 1.08 only shows 48 & 49 again large jet...
yeah, im kind of surprised it worked as well as it did. you see a bit written about the 101's used but not much on the 114. pretty stoked. Hopefully this thread will help some one out there, I didn't find a damn thing on the net about a 250 i6 and jetting w this carb.
