Can anyone help?

[daredevil]

If it were me I'd just switch to a Carter / Edelbrock 750... I've never had much luck with holley's myself, Isn't once you backfire a holley you blow the power valve???
Carters are just so easy to tune..... just my two cents.

They ave fixed the power valve problem. What color are the plugs ? If they arent fouled soot black you probably aren't to fat.I have heard the avenger NCTM numbers are exaggerated.

 

[daredevil]

Cfm numbers. Damn iphone

 

[Meep-Meep]

I found the packet from the performance shop that built the engine. Here are the particulars:

1) Holley 0-80870 Carburetor, Street Avenger, 870 cfm, Square Bore, 4-Barrel, Electric Choke, Dual Inlet, Silver

2) Eldelbrock Performer 383 INtake Manifold

3) Comp Cams 23-224-4 Cam Shaft (Camshaft, 3-Bolt, Hydraulic Flat Tappet, Advertised Duration 274/296, Lift .488/.491, Mopar, Big Block)

4) Ported and Polished 440 85cc Heads

5) Compression Ratio is 9.59:1

870 CFM You have too much carb! I bet that cam would be better off with more compression too. Another question. What is your cranking compression PSI?

 

[scotts74charger]

same prob here(also on a 383/727 combo and i only went from a 600 to a 750 both holleys am seriously thinking of going to a eddlebrock