okay i bought a holley 6210 spread bored this weekend off a guy with two thermoquads at iola. Now i wanna now are these any good its got mechanical secondairys it appears to be a double pumper except i think some changed a bowl. Because it should have a two fuel lines one for each bowl correct any way educate me the good bad and ugly on these thanks bryan

great carb, 50 cc acc pump, Got rid of the tq's long ago because of acc pump benefits of the holley.
only one feed, transfer tube to secondary bowl.

any idea on the cfm or how to tell the cfm i might run it on my 440 thats 10.1 comp with a comp cam 484 would this work good? other wise im gonna probably put it on my 460 im building for my 77 ford f250

650 cfm.
works great on bb or smallblock.
for street, no need for more cfm than that unless racing app.
easy to tune, no bogging issues wth the dbl pumpers.
not as economical unless you keep out off the acc pumps... hard to do, because of enjoyment of responsiveness.

I've always felt they were great carbs.
I ussually find the primary jets are a little too SMALL at no. 60. I go to either a 61 or 62.
Make sure the secondaries are open enough at idle to show a square in the transfer slot, then use the primary side to adjust the idle speed. Actually you want pri, and sec, to both shop the same square. Double pump, with single feed.