Differences in Q-jet vs 585 Holley vs 4GC

[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.

[james schaechter]

Originally Posted by Mark Yacavone

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.

Mark, that little carb option is still rated at 274 on our car. 66 nova stickshift. I have heard from a couple racers (not in Midwest) that said the 585 was a legal replacement on the stocker 327 275 but I really really doubt that is legit. We run the QJet on that combo in stock and it works well. ( and UH OH! we actually have the product engineering bypass regulator on our car as well)

[impstocker]

With my 65 Impala build, I am able to use a 585 Holley on my 396/325 (410 CI now)I do have one to use, just need to find a manifold. I always feel more comfortable with Holleys too, opinions vs Q-Jet. I will probaly try both anyway.

Will Lamprecht I/SA 65 Impala looking to 2016 season.

[impstocker]

Just a thought, maybe better fuel distribution through the manifold with the Holley vs the spread bore Q-Jet even though more CFM with Q-Jet?

Will Lamprecht -

[Mark Yacavone]

Originally Posted by james schaechter

Mark, that little carb option is still rated at 274 on our car. 66 nova stickshift. I have heard from a couple racers (not in Midwest) that said the 585 was a legal replacement on the stocker 327 275 but I really really doubt that is legit. We run the QJet on that combo in stock and it works well. ( and UH OH! we actually have the product engineering bypass regulator on our car as well)

Yes ,I know all about that deal.
Joe Sr. and I raced a 66 Chevy II way back when you had to use the Holley or Carter , and not the Q jet.
Still possibly the fastest SS/J car in the country at the end of 1973..Record holder, and No. 1 qualifier at the World Finals in Amarillo...with the 540 Holley.
You could use a Q Jet on a 67. This is the reason ,I believe , that Larry Tores built the 67 post car.
Anyway, I think we were talking about SS/GT here.
Don't you think the small Holley should be rated less than the big one, or the Carter, for that matter?
Also nobody has mentioned the little Corvette WCFB yet, on the 520 head combos

[nhramnl]

Originally Posted by james schaechter

Mark, that little carb option is still rated at 274 on our car. 66 nova stickshift. I have heard from a couple racers (not in Midwest) that said the 585 was a legal replacement on the stocker 327 275 but I really really doubt that is legit. We run the QJet on that combo in stock and it works well. ( and UH OH! we actually have the product engineering bypass regulator on our car as well)

And let me guess; the car is quicker, but only because you're carrying less weight down the track, with that lighter wallet!

[Joe Schaechter]

Originally Posted by nhramnl

And let me guess; the car is quicker, but only because you're carrying less weight down the track, with that lighter wallet!

I like it on our car with the Qjet. When we were running the 4GC and Holley carb combinations it was never a problem with our old fuel system. We found those two carbs are more forgiving. The Qjet was harder to get consistent performance prior to adding the Product Engineering bypass. Everyone has their own approach to make their car work and opinions are going to vary on where to spend their money.

[dmir55]

Holleys are easier to change the boosters on. Just a thought.