Re: Holley 650 double pumper spread bore
The spreadbore double-pumpers IMO are one of the best all-around street cars ever built. Great gas mileage, make excellent power, they FIT THE CAR unlike some other carbs (*cough* Edelbrock *cough*), and are extremely easy to work on.
The whole "bog" thing is usually driver education. Never forget, it's a MANUAL SECONDARY carb! You can't just stomp on it like a cockroach and expect the same results you get with a vacuum secondary carb. Once you learn know how to drive with a trace of finesse, you'll see.
To tune it:
Get your timing set right. Which is, about 36 - 38° of advance at 3000 RPM, with the vac advance unplugged. Make sure your timing mark is accurate; they usually aren't, and can be WAY WAY off of you have an aftermarket timing pointer and a stock crank damper. That combination usually results in about a 35° error. This will cause the motor to "bog", have no response, run hot, get poor gas mileage, and generally run "lazy".
Tune the primaries by first leaning the jets down until it just begins to barely surge going up a slight hill in high gear at the lowest speed you would realistically do so; usually 35-40 or so. Then go back up 2 sizes. Then raise the power valve (stock is a 6.5 IIRC) until the tip-in sag with light throtlle goes away, then go up 1 - 2 more #s. It'll usually end up with a 9.5 or 10.5 in a street car.
Set the curb idle speed to where you want it (700-750 or so), then take the carb off and turn it upside down and look at the transfer slot. If there's more than about .050" of it exposed, back off the curb idle screw to set it to about .030", and open the secondary idle stop screw by an approximately equal amount. Put the carb back on and adjust the idle speed, then the mixture screws for highest vacuum (you'll probably have to turn the idle speed back down as you do this). Turn them both all the way in, counting the turns, and turn them back out to their average, plus ¼ turn. Repeat this whole paragraph until the transfer slot has less than .030" showing below the pri throttles, the idle speed is where you want it, and the idle mixture screws are within 1/8 turn of each other and ¼ turn out past max vacuum.
All of that should make it run ALOT better. Then all you have to do is learn how to roll into the throttle a little bit, instead of just stomping it to the floor. If it still has issues, post back up, and we'll try to help.