i found out that stock 500 cfm has 2, 73 jets, i read in a forum that someone had a 258 jeep engine and rejet the carb with 65's, so im going to try it and post the results. http://forums.off-road.com/jeep-short-w ... -2bbl.html
holley 500 cfm rejeting
- Thread starter 64 200 ranchero
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wsa111 did extensive testing to get his up and running.
viewtopic.php?f=1&t=29740&p=215106&hilit=holley#p215106
viewtopic.php?f=1&t=29740&p=215106&hilit=holley#p215106
i re-jet it with 68's, wow what a difference that made :mrgreen: still a tad bit rich though
I had a 1986 Mustang with a 2.3 liter 4 cylinder engine that I hopped up. It had big valves, port work, Esslinger circle track intake, 500 cfm Holley, JR header, etc. I swapped out the original 73 jets for 69's. then 65's. The 69's were much better for power and didn't run rich like the 73's. The 65's were still great for power, but a little down on power at the top end, with no rich issues at all and 3 to 4 mpg better gas mileage than the 69's. Ran it with the 65's in the UK for 3 1/2 years, then 69's in Germany for 3 years. If I wanted a decent combo of mileage and power, I'd go for jets around the 65's. If you want a little more top end, I'd say the 68's you have would be about perfect, but might be a little rich down low. IIRC, I used a 6.5 power valve after checking vacuum reading at idle. Tried an 8 and a 6.5, but settled on the 6.5 PV. I used a 31 shooter instead of a stock 25 for a little more fuel shot for transition from idle to power circuit. That may be dependent on your little plastic throttle cam though. IIRC you measure for vacuum at idle and then cut that reading in half to be close to what PV you need.
Darrell
Darrell
i have an adapter
Gene Fiore
Famous Member
IMHO I believe jetting will be different if you are using an adaptor versus direct mount. Jetting of course will also be affected by ambient temp and altitude so what works for one person may not work for someone else. I'm wondering what altitude you guys are at. I have had different experiences jetting my 500 Holley 2bbl but then I have a decent cam and about 10:5 to 1 compression. Also keep in mind my goal is for the most power at the track and don't care about economy. Just for what it is worth this is what I found out recently at the dragstrip.
I have the 4412 Holley 500 right out of the box and it seems to run pretty good with my build, but I suspected that it might be a tad rich ( for some reason my carb came from the factory with 74 jets instead of the 73's they are supposed to have). The track I run at is 1200 feet above sea level and the temps this past weekend were around mid 60's. Before I went to the track I re-jetted down to 72's expecting to pick up some et. This did not happen. I re-jetted again after a few runs to 73 and it picked up almost 2 tenths in et and 2 mph. Just for what it's worth....
I have the 4412 Holley 500 right out of the box and it seems to run pretty good with my build, but I suspected that it might be a tad rich ( for some reason my carb came from the factory with 74 jets instead of the 73's they are supposed to have). The track I run at is 1200 feet above sea level and the temps this past weekend were around mid 60's. Before I went to the track I re-jetted down to 72's expecting to pick up some et. This did not happen. I re-jetted again after a few runs to 73 and it picked up almost 2 tenths in et and 2 mph. Just for what it's worth....
i dont care about economy either, im just trying to build somthin to smoke the little ricers at the track, my car ran great with the stock 73 jets, however it would put out alot of black smoke and i was worried of contaminating the oil and washing out the rings, when i put the 68's in my car picked up some accel and didnt loose any top end, i have no idea what cam im running, i know its not stock, it has a slight lope
Have you done a plug reading yet?
my plugs were black from running rich with the 73's, i have not checked with the new jets yet, ill see tomorrow
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