I'm thinking of trying different carb on my 69 SS396. I currently run a 750 d.p.but want to try a 870 vac. sec. Street Avenger. Engine is a 427 with about 11:1, .561/571 lift Comp. cam, 3000 stall, 410:1 gears. If anyone has any info. please reply. Have been told this carb would work well with this engine combo. Thanks.
Its a nice carb, but like all 850's its jetted rich (78/82 w/front and rear power valves). I had one on a 454HO and it ran nice - no soggy bottom end, great response, etc.
Personally, if you need a 800+ cfm vac sec carb, I would go on ebay and get one of those ZZ502 850cfm take-off carbs. I've seen them new go for around $250, and its basically the same thing (less the quick change secondary can) and you save quite a bit of money over a new 870. The Avengers have that shiny finish that looks good coming out of the box, but turns crappy looking pretty quick.
Score the 770 avenger. That's a better fit for sure. I did a little testing at the track. Car ran times in my sig with a Prosystems 1000hp, yanked that carb and put the 770 back on the car. I had the need to slow it down as I have no cage fro running under 11.5. Car ran a best of 11.58 with the avenger. Prior to the carb swap, change in rear gear, box stock avenger 770 jetted 74/84 on my car ran 12.1x. Electric choke worked great, plenty of vac ports, and SHINEY too!
Had an 870 Avenger (out of the box) on my 408CI motor. The 870 was far too much carb for it. Not that it wouldn't get by, but the throttle response was real lazy. Probably good for a 4500 - 7000 RPM motor, but crappy below it. Now running a 670 on an Air Gap oval intake with the heavy (black) spring - throttle response is like fuel injection.
just rejoined this fine site, and reading your post, Ever think about a demon? I have a 66,ss L78, and I'm trying a Mighty Demon, had to do some jetting, but ! I like it:hurray: ton's of throttle response, no bogging,and hold on to your pants .Jusr my 2 cent's worth.
I went with the 870 Street Avenger. Just came back from trying it out. Works great. Same bottom end as 750d.p. but far more high r.p.m. power. I think I made the right choice.
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