hi there i have a 85 mustang with a 302 with tf track heat heads and tf stage 1 cam an edelbrock victor junior manifold and a c4 with a 3500 stall. i was sold a holley street avenger 770 carb but this thing has been a nightmare it runs super rich, i tried putting in number 68s in the primarys but this did not help i also have the yellow spring in it .If anyone has any suggestions they would help .

 

That carb is far too big for your engine IMO.... [:-]

 

i do have a street avenger 650 would that work? or do you rec something else.

 

i think the 650 would be better... that's what im running.... though not an avenger... dont like vacuum secondaries...

 

thanks i will give it a try and let ya know later.

 

is it fouling plugs?may have wrong power valve opening too early.make sure idle fuel is right.if its got 68 and still running rich thenits not the jetting.maybe metering block gasket bad, or wrong plugs.check coil also.770 is NOT too big, with the correct tuning i could run a dominator on my 306 without killing plugs.770 is a measure of air coming in, not fuel.and so 650-850 use basically the same metering blocks this carb actually flows more air than you need, not fuel.your also loosing vacuum with it.it should run fine with proper tuning, but 650 is probly more your range depending on how hard you turn it.i run a quickfuel that flows 680 cfm and turn it 7100 on the bottle on my 302.if i got a solid cam i would turn it 8000 and probly buy a 750.