The Money Pit

I've been looking into a carb swap from the Edelbrock 1904 to a Holley 3310 and as is usual,I read too much. I find one site that swears by Q-Jets,and most others curse them.I thaught I would be able to save a bundle by rejetting and tweaking the power valve spring,and then I stumble on a fuel starvation issue.
Is the bowl on a Q-Jet big enough,or can the seat be enlarged to support high horse engines?Seems Holleys have two fuel bowls and it would make sense they would last longer before they run dry under extreme acceleration.I've got 110gph pump,but how fast can you pump fuel through a hole the size of a pinhead?

wayne_69_427

I had both on mine and I chose the Holley by far.

PRNDL

If one Qjet isnt enough, you could always try using two!! :) hmmm... does an intake exist that would accomodate 2 X 4bbl Qjets? :) Your original question is an interesting one..... seems like people always switch to holley or (more recently) demon when they go for high performance. And they always point out that even GM didnt use Qjets for their high performance engines, ie, L-88, LT-1, LS-6, 435 hp engines all used holley carbs. MJ


[Modified by MNJack, 8:40 PM 2/19/2003]

71DropTop

I have asked the HP question on q-jets many times in the last couple of months (not that I need to Know for my benefit) I'm lucky to be at 400 .But I did ask out of curiousity and was told by Engine builders that there are more than you think pushing 600+ with obvious mods to Them!!! :steering:

Gordonm

The machine shop I used to use was running a big block Chevelle with a Q Jet. It ran low 10s so I assume it was making over 500 HP. It was heavily modified though.

The Money Pit

Most likely I'll knuckle under and get the Holley,I'm just tight with the cash right now and was looking for an alternative means to an end. Truth is you can make a hunk of coal into a diamond.The fact is it would be more expensive to make,and most likely would not be as beautiful.
On a side note I discovered the LS-7 made 465hp with a Q-Jet in 1970.The concern I had was the peak hp was only 5400 rpms.Do you think 6500 rpms would suck the bowl dry? :steering:


[Modified by The Money Pit, 2:12 PM 2/20/2003]

Gordonm

The LS7 was never released for sale in a car. They were over the counter engines. The LS6 used a Holley carb and made 450 HP in 70 and 425 HP in 71 with a Holley carb also. I'd be curious t oknow where you saw a LS7 with a Qjet. Never heard of it. What kind of Holley are you looking for. I have been looking to sell my 750 DP if someone was interested.

Neo Fender

Was the LS7 sold as a turn key product or was it just a long block only?

thejaf

I have a Q-jet on my 406. It has a Holley mechanical fuel pump, return line capped. I get fuel starvation after 6000 rpm, car just falls on its face. I don't know if it's the Q-jet, or something else, but just thought I'd share it with you.

American Boy

Anyone heard about brass float for Q-Jet? They are smaller than the regular float so they allow more fuel in the bowl preventing starvation. The Q-Jet are more difficult to tune right when you don't know them. IMHO it's the only reason why everybody gets Holley carb.

For my current engine buildup at near 400 hp I'll keep the Q-Jet since when they are fine tune, they give the same performance and gets better MPG.

But in the end, it's almost like a religion. :blueangel:

Stephan

Guru_4_hire

Edelbrock makes a dual carb intake manifold

honaker

I'm running a 383 at about 450 HP. I rebuilt it and rejeted in accordance with the papers that lars has put out. I also bought a hayns rochester book, not much help but it had a few good picks to help put it back together. I also took the butter fly shafts and thinned them to about half there size. I got that tip from anothe small block chevy book. This set up should work up to 550 plus HP.

Gordonm

According to my books the LS7 was sold with an intake and an 850 Holley DP. Exhaust, water pump, Distributor,starter and fuel pump were not included. Basically the LS7 was a 454 built to L88 specs.