Quickfuel SS 850 Mechanical Secondary for a 440

[cudabob496]

for a stock 440, an 850 is too much.
750 max!

I had an 850 on a mild built 440.  Bog machine.

[dodj]

for a stock 440, an 850 is too much.
750 max!

I had an 850 on a mild built 440.  Bog machine.

I'm thinking you had something else going on. My 440 is stock except for a MP .484 lift cam. The QF-850 dp on it is great IMO. Better idle, better response. Did my 3310 have problems? I'm thinking it must have because the QF-850 makes it feel so much better.

[cudabob496]

ya, it came with the car, so I don't know how well the carb was tuned.
Though it was a brand new Holley 850 DP.
"bog machine" was not a good term for me to use.
Car had stock converter, and 3:23 rear gears.
Was not responsive off the line.

[Strawdawg]

It's really easy to size a carb.  If you are reading more than 1.0 in-hg vacuum at wide open throttle at your particular red line, you need a larger cfm carb.  That is for a street car.  If you have a strip only car, then it should be no more than about a 0.5" hg.

Most street cars have at least 10 " hg vacuum at idle and that is enuf to obtain a sufficient signal to pull fuel properly out of the carb so that the mostly standard dog leg boosters will work fine.

Double pumpers can be made to work with almost combination but it make take more tuning to work with automatics, factory stall, and/or high geared rear ends.  In those cases, tuning, and learning to use your right foot off idle makes all the difference in the world.

[dodj]

Car had stock converter, and 3:23 rear gears.
Was not responsive off the line.

Mine's a 4 speed with 3.55 rear. Big difference there.

[cudabob496]

Mine's a 4 speed with 3.55 rear. Big difference there.

ya, my 496 now has 3.91 gears, and a 3500 stall, so the car
and the 850 are very happy together!