[DAVID GAGNARD]

I have both a Holley and a Demon carb on my 2 cars..........600 DP holley on a 350 hp, 351-W in my Mustang, and a 650 DP Demon on my 472 hp 331 stroker in my race car.......love both of them, they are matched and jetted to the engines.........

The formula for carb size goes like this..........max rpms X cubic inches divided by 3456.........this will tell you the cfm of your engine assuming it's 100% efficent, which it will not be, add another 50 to 75 cfm to your final number and that will give you the size cfm wise you need for your motor......jetting it correctly is another story.....

on the dyno, my 331 stroker used a max of 586 cfm of air at 6500 rpms, so the 650 is just right.......

on the 351-W I have tried 7 different carbs, all testing done on the drag strip and highway for mpg testing......the 600 cfm beat them all hands down, mpg wise and 1/4 mile wise......I tried 3 different 600's, a 700 cfm marine carb, a 715 cfm carb, a 750 cfm carb and a highly modified 750 cfm carb, the 2 750's were the worse, all carbs tested were Holleys......the best one and the one on the car now is a 20+ year old Holley 600 dp a buddy was throwing away, gave it to me, I rebuilt it and re-jetted to my needs and it's been on the car for 5 or 6 years now and probably 15,000 miles without being touched!!!!!!!!

David