Too Much Carb?

I have a 360 that is at 10.6:1 compression and the XE268 cam. I have run a Holley 600 vacuum secondary, a BG 725 vacuum secondary and a Holley 750 vacuum secondary. While the 725 and 750 give me noticable increase in power above 3500 rpm the throttle response in the 1000-3500 rpm of the 600 is much much more satisfying than either the 725 or 750. Plus the car is no slouch with the 600 running a best of 13.7 @ 102. I have all three carbs on the shelf and will from time to time put the bigger ones on but I keep going back to the 600. NOTE: the BG725 was much much worse in regards to throttle repsonse below 2000 rpm than even the 750 Holley.

The 850 is going to be all together too much carb for a car with a relatively mild cam like the XE268. The throttle response for street driving will not be good and the engine will never beable to use all the cfm capability of the carb. If you are extremely talented at tuning carbs and are willing to switch boosters and bleeds you may be able to get it to work ok.

You can't compare the 6-pak or even the spread bore carb cfm to a square bore carb. The 6-pak ran most of the time on 2-bbls and the primaries of the spread bore carbs were tining and the secondaries never fully opened on these cars in stock form.

Take the 850 and see if you can trade it for a 650-700 cfm carb, you will be much happier in the long run.