You will need 24 to 26deg of idle base timing for that 286H-10 cam to idle sweet.
recurve the distributor to allow this and 34-36deg at max advance. (10deg mechanical advance curve)
Get a 4.5" power valve.
No amount of carb monkeying or swapping carbs will work untill you give the engine the generous amount of timing it needs at idle.
The 670 SA holleys are intended for very mild cammed motors.
It will cost more to dial in this carbs fuel curve than getting a real deal 750 cfm hi perf carb.
Once the spark curve is correct the 670AS carb may or may not need the IFR and or the IAB fine tuned.
The WOT power jetting will probabily need correcting to.
A 750 (any 750) will make more power and run better on that motor in every respect.
Get the 750 eddy or the 800 thunder series.
The 800 AVS thunder carb IS NOT TOO BIG.
If you get the version with electric choke start your calibration tuning
using the base line of the manual choke version.
Or get a 750 holley Not a avenger series. Can be VS or double pumper.
The street advenger series carbs are for mild camed motors.
Find a good used 650-700 DP holley and upgrade it using the proform HP body
Or find a used 3310 750VS and upgrade that using the proform 750VS HP body kit.
The vastly better performance and tunability of the HP carb body outways the lack of a functional choke.
Do not be afraid of a DP holley . It will be good on gas and responsive as hell once upgraded and dialed in.
The avenger series holley are notabley lame on perf motors.
Thats why they cost less.
Last edited by F-BIRD'88; 09-03-2012 at 12:14 PM.