Q-jet and Holley

[Mickey Whaley]

Originally Posted by Weekend Racer

Chevy small block 350,make 597 hp with holley 750, and drop to 562 with Q-Jet .What can I do?

Any input Thank,

why did you take the 750 off??

[Weekend Racer]

Mickey, Just dyno test ,on my ss engine.

[Mickey Whaley]

Originally Posted by Weekend Racer

Mickey, Just dyno test ,on my ss engine.

Q jets are funny get a good one it really will be a surprise the difference!

[Weekend Racer]

Yes ,mine need some upgrade or tuning !
Thank,

[Mike Taylor 3601]

Turbine is used to mearsure air flow (cfm) engine is using,usaully has cat (carb air temp) sensor mounted in it also.
My engine does'nt make near that power, pure stocker,my Q jet will match HP all way through and have about 3lbs. torque less @ peak than 750 holley. I compared on 351C on time w/ my q,jet 750&850 dbl. pumps and had same results.
I leave turbine off and mount cat sensor on carb to where it picks air temp going in carb so correction is repeatble.

Mike Taylor 3601

[Weekend Racer]

This is very interesting subjet?
Thank a lot everybody!

[vic guilmino]

i removed a 780 holley and
i put a q-jet on my 429 ford
same mph but et was .2 slower
carb when very rich in the first 100'
need help with that

[eddie c]

Originally Posted by Mickey Whaley

Q jets are funny get a good one it really will be a surprise the difference!

My apologies for going a little outside of this thread, but I have always
wondered why some QJs perform much better than others. I realize there could be many theories on the subject, what makes one QJ fly and the other a dog! tks ed

[Weekend Racer]

For myself I have a bone in my engine ,it is the Q-jet, or a distribution problem from the spacer and intake.

I hope , I am not the first one with an drop of performance when we switch the Holley for the Q-jet?
Thank,

[Alan Roehrich]

Originally Posted by Weekend Racer

For myself I have a bone in my engine ,it is the Q-jet, or a distribution problem from the spacer and intake.

I hope , I am not the first one with an drop of performance when we switch the Holley for the Q-jet?
Thank,

Sounds like maybe you need to see about borrowing another carburetor, and maybe talk to someone about intakes and spacers. I think a 35HP loss is far too big a difference to be acceptable from just a carburetor change, if the two carburetors are close to the same size.