Jetting questions

[BDT 1967]

I have a 67 stang with a 289 bored 60 over, it has a holley 650 carb and a edelbrock highrise intake and a hei ignition, I left the jets in the car that came with it, I took the plugs out the other day to look at them and they were black as hell. I know that I must be running a little rich. What size jets would you recomend me to put in this car. by the way it doesnt smoke when running and it doenst seem to be loading up, here is a link to a video of it running *( you know i could talk about what its like all day long but for you to see it for yourself would realy help.) http://bdtracing.125mb.com/vid9.htm

 

[2bav8]

I like to chang jets in steps of 3.
So, if you had 70 jets in the carb now I'd try a set of 67s to start off with.

 

[BDT 1967]

Thanks for the imput

 

[iskwezm]

is it running rich at idle?cruise? or WOT?

 

[302 coupe]

by a jet kit, some new bowl gaskets, and some nylon bowl screw washers. Tune to your hearts content. As a baseline, I would say 67 front and 73 rear should be ok, which is stock jetting on most 650's.

 

[jbuening]

Any idea what rpm's you are idling at? Sounds to me like it is idling a bit too high.

 

[66moneypit]

I have a 67 stang with a 289 bored 60 over, it has a holley 650 carb and a edelbrock highrise intake and a hei ignition, I left the jets in the car that came with it, I took the plugs out the other day to look at them and they were black as hell. I know that I must be running a little rich. What size jets would you recomend me to put in this car. by the way it doesnt smoke when running and it doenst seem to be loading up, here is a link to a video of it running *( you know i could talk about what its like all day long but for you to see it for yourself would realy help.) http://bdtracing.125mb.com/vid9.htm

Just curious, any head issues with the engine bored that much ?

 

[BDT 1967]

No I had the heads done to match the displacement, it is about 301 cdi. But i dont know for sure. And I have no idea what it is idling at right now, the day that I took that video it was hella cold out here in kansas, so the choke was on. but i do think that it is a little high. Of corse that engine only has about 250 miles on it, and i would hait to drop it down to soon. It has a pretty agresive comp cam in it, and that also may have something to do with my hella black plugs. It seems to me like the thing is running just a little rich on the idle, but i dont know for sure thats why i put the vid up. It doesnt smoke, but it does smell a little gasy in the shop after i let it idle for a while. I bought the jet kit from jegs, and i will start at what ever you guys think.

 

[D.Hearne]

Don't rejet it, till after you've driven the car. You CANNOT accurately jet a carb for running conditions with it just idling. If you haven't driven it, you may just need to set the idle mixture screws and or have a blown power valve that's getting the plugs black. When I jet a carb I go up or down in 4 sizes, but only after it's been driven under the actual conditions in which you plan on using it. Idling in the driveway doesn't constitute driving conditions, the main meterting circuit hasn't been used in that case, that's where the jet screws come into play.

 

[jbuening]

I agree, if it is fouling the plugs when it idles then adjust the idle mixture screws. With only 250 miles on the motor, did you put new plugs in when you did the fresh rebuild? If it is fouling your plugs after 250 miles, then i'd check the idle mixture screws and even the plug gap or weak spark. Don't forget to check your timing too

 

[iskwezm]

check your vac, then see if its the right PV

 

[BDT 1967]

I drove the car to a show about july, so it does have some road time. The i didnt think that the plugs were fowled but I took them out just to have a look at them, thats when i discovered they were blackend. I did put new plugs in the car when i did the overhaul and i put in a hei ignition, so i think that its probably getting the right spark. I messed with the idle adjustment and it seems to be running fine, I put new plugs in it and went about 50 miles, I think i am going to check one of the plugs again to see if this set is getting black. Those plugs may have just gotten that way from initial startup.

 

[D.Hearne]

Wow, you must love buying new plugs Why not just clean em ?

 

[BDT 1967]

Well when I bought the plugs the first time I got autolite standards. Then when I pulled them I decided to replace them just for the hell of it and get autolite triple platinum. I will not buy another set. Too much cash for the stang that gets maybe 200 miles a year.