500 AVS2 or 650 AVS2 ???

gtxdude said
As some of you know, I've been throwing carbs at my 65 Dart 318 for a couple of years. Have a 600 Eddy on there right now, not bad but looking for a change (don't ask me why). Long story short, looked at posts going back a few years about carb sizes for 318 and everyone's thoughts. It's a 318 with 230hp at the crank, about 180hp at the wheels, 8.25 3:23 posi. As some of you know we do a lot of cruising, long trips ( Route 66 a couple of years ago, awesome trip)
It's going to be AVS2 500 or 650 I really want the 500 for mpg but I'm leaning toward the 650 to make sure I have enough carb (never been over 4500rpm ) My question is, can I calibrate the 500 up or am I better calibrating the 650 down to be a little bit more fuel efficient? I pretty much know who's going to respond and I appreciate all of your guys input.
For what ever reason Summit just knocked $90 off there AVS2 650 so that's what has my asking, Tilly :)

Well, you're thinking isn't exactly right here. You cannot really tune "up or down" regarding carburetor SIZE, but rather rich or lean and that's about it. However, using the AVS makes that a little different, since they are regulated on the secondary side by an adjustable air door. So you can actually back off on the flow on the secondary side some. Since the more the door opens, the more fuel is pulled in. By making the door more difficult to open and also limiting the opening, you can back off the total flow of the carburetor some. I would use the 650, because I believe it will be easier to limit IT rather than try to make the 500 match up. Just one peon's opinion.