I have a beede tach with 4 settings on the back. 1 2 3 4. What number should it be on.

Hey guy's what's going on. Glad to be back home. If you guy's didn't know me and my wife were on that cruise. What a vacation.  . Well anyway's like I said glad to be back on land.  . Try to get pics, but I have to find camera and usb cord to upload pics.

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 i have a bbf 460. just put 5,000 in the motor to restore it. big pistons mild cam roller rocker everything running about 500 to 550 hp. can get 5700 rpms when opened up wide open. has a tunnel ram with dual carbs. 2 holley 450's vaccum secondary. runs great. i think. maybe a little lean on top end. no hesitation. gps average speed 67 to 68 mph. question is the 450's enough. i want to put 2 750's. is that to much. should i stick with holley or eldebrock. vaccum or mechanical secondary. or double pumper. what do u guys think he should run or should he just leave it alone.