rejetting holley 670 street avenger carb

[Terrybneal]

I have a 670 holley carb and it is running a little rich,which jets should I change to. Do ya buy the jets separately or in a kit?

[Scotty_S-15]

Probably best to buy seperate jets. You can buy a whole kit, comes in a nice box, and it\'s a real bargain considering all the jets you get. BUT, about half of them are so far out-of-range, you\'d never, ever use them. I do have the kit, and the box is handy to throw power valves & stuff in too.

........... Which jets to change? Does the Avenger have secondary jets, or a preset \"plate\"? When\'s it running rich, idling, cruising, or under full load? If the plugs are just black in general, change the primary jets, but also consider the power valve might be coming in a little early if it\'s got much of a cam. How\'s the float levels?

............... Good Luck!

[link523]

try www.mortec.com there is alot of good tips for tuneing holleys and how to pick the wright power valve

[Terrybneal]

Ill give yall of the info I have,maybe yall can help me better. The carb is a Holley Street Avenger,part number 0-80670. I have a Eldebrock air gap intake.The cam is a Crane Energizer Part #100052 .272 int.272 exh.The only other thing is the motor is bored .060 over,headers, and a three angle valve job with stock heads. It is a daily driver. The max rpm is usually about 5000rpm and the cruise rpm is about 3000 to 3500.It isnt fouling the plugs and when I changed them last time,they werent really black and soutty. It is running rich at idle.I can tell by the smell.Ive tried leaning the carb out and playing with the timing, but that makes it run bad.I looked at the holley web site and www.mortec to try to figure which jets I have, but cant find it.I changed the spring to make the secondarys come in smoother. I used the lightest spring in the kit.Hope yall can help!!

[wild85]

I have the same carb.



Scotty! It has 65/68 jets. and comes with a 6.5 power valve. I have 350hp at 5500 rpm and 360 tq at 4500 rpm and run the stock jets and a 4.5 power valve with a cam that has 236 deg at .050. Although I have a stumble when using gas, it works pretty good. I think the floats may be low and it is running out of fuel.

[MARKYMARK]

did you have to turn the idle screw alot when you got the engine running. if so your probly out of the idle circut. try opening the secondary butterflys a little this will let you turn the idle down. you may have to remove carb to do this.set screw under secondary stop

[gdmclnh]

I have a 355 CI sbc virtually identical to yours. My cam is the 100172 cam. 274 deg, 218 @.050\" lift. I use manifold vacuum with initial timing about 12 Deg. Tried ported vacuum, but it didn\'t work well. If you haven\'t, try full manifold vacuum, It may let you close the throttle plates and allow less opening of the idle air mixture screws. Three turns open is a lot. Mine runs and idles great on manifold vacuum. Jets are the original 65 and 68s. I may try going up to 67 and 70s. It runs a little lean.