Differences in Q-jet vs 585 Holley vs 4GC

[JP Schuster]

Anyone ever tried them on the same motor and noted the ET or HP differences?

[tj310]

I have run the 327 in SS trim that uses 4gc or Q-jet and found the difference is accurately reflected in the HP factors. My motor is low budget.
I spoke to a racer who uses the 327 back and forth between the Holley and Q-jet he claimed Holley was a little quicker . ---Trevor

[Mike Taylor 3601]

Only comparison I have is I test my Q-jet against 850 dbl. pump holley,just out the box carb on my 305 dynoed pretty much same all the way through the pull,holley made 3lbs more tq. @ peak tq..
Then later had a 351C 4bbl head street/strip engine put my q- jet on it and got same results as the 305 identical except about 3lbs. tq. difference @ peak tq.
Not really what you asked but maybe help some how.
Mike Taylor 3601

[Dan Fahey]

Originally Posted by tj310

I have run the 327 in SS trim that uses 4gc or Q-jet and found the difference is accurately reflected in the HP factors. My motor is low budget.
I spoke to a racer who uses the 327 back and forth between the Holley and Q-jet he claimed Holley was a little quicker . ---Trevor

I had one of my Qjets reworked by Val Headworth.
It was flow tested and had new Air Bleeds and new parts.
It ran a little better than the ones I reworked.
Just felt better, crisper, no bogging.

Dan

[Supershifter55]

What is the"585 Holley" and what combination did it come on?

Thanks, Gary Howe,

[JP Schuster]

585 CFM Holley and I believe it was on 327 in Corvette's for a few years in the 60's. I'm not sure of the exact details because I have never ran this before. Just word of mouth.

[Dragsinger]

The "585" Holley was on a 1966 Corvette 327/300. Quick Fuel builds a legal replacement #VS585R

I have it on my Super 10

[Jeff Jewell]

Originally Posted by Supershifter55

What is the"585 Holley" and what combination did it come on?

Thanks, Gary Howe,

The 585 was also on the 427/390 engine in 66 and 67 Corvettes. Way too small for a 427...

[Ernie Neal]

The 585 was used on the Corvette 327/300 66/67 a 585 was also used on the 350hp engine in 65/66 it had jet plates on both ends. The carb we are talking about has 1 9/16" throttle plates. Don't confuse this carburetor with the 66 chevy II and others with 275 hp and a holley it only has 1 1/2" plates.

We use the 67 327/300 comb in the Sunfire my son drives. In our case the holley is better due to the hp factor, but may not work as well in all cases.

Ernie Neal
SS 354

[Mark Yacavone]

Originally Posted by Ernie Neal

The 585 was used on the Corvette 327/300 66/67 a 585 was also used on the 350hp engine in 65/66 it had jet plates on both ends. The carb we are talking about has 1 9/16" throttle plates. Don't confuse this carburetor with the 66 chevy II and others with 275 hp and a holley it only has 1 1/2" plates.

We use the 67 327/300 comb in the Sunfire my son drives. In our case the holley is better due to the hp factor, but may not work as well in all cases.

Ernie Neal
SS 354

Yes, the 66 540 Holley should be rated about five more than the 4GC, but so far, NHRA doesn't want to hear about it.