Spread-bore carb questions

Been sitting here at work bored with nuthing but gasoline and horsepower on the brain [img]/phpBB/images/smiles/icon_lol.gif[/img] and I was thinkin about ditching my Edelbrock 750 carb and Performer intake on the Bronco's 460 in exchange for a Performer RPM and Q-jet type carb. My reasoning being that, first of all my Edelbrock carb pisses me off at times, the throttle doesn't operate smooth and sticks at times, and sometimes it decides it wants to flood my engine out on cold mornings, where other times it runs fine... so I would be happy to see it go for a little higher quality carb. I think that with the RPM intake I won't loose hardly any grunt, and will breathe a lot better up over 3500rpm... and I've heard great things about the Q-jet type carbs, specifically great mileage and driveability along with excellent power when the monsterous secondaries open up. I know there are some factory Rochesters that were up over 800CFM rating, and also Edelbrock has their Q-jet 850 carb, although it's pretty pricey. I also noticed that Holley made some spread-bore style carbs when looking through eBay, so I was hoping you guys could give me some input on if this sounds like a good idea or not... if I will get what I am expecting out of the swap, and steer me in the right direction for what type carb to look for. I may get one off eBay, or also my friend's dad back home has a shop full of old carbs, he might have something he'd sell me for cheap. Any input?

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'86 Bronco fullsize, 460, E4OD, 6" lift, 35" BFGs, 4.56 posi

'85 Ranger, 340hp 289, T5, Cobra wheels, 245/45/ZR17, 4.10 posi 7.5"


<font size=-1>[ This Message was edited by: Motorhead on 3/3/05 1:33am ]</font>

When it come to making "power" many will say that the 650 DP Holley SB is junk. While I cannot contest that, I can say that it is good for mileage. I had mine on my 73 Torino with a 460 and I got very good milage with it. Sold the engine and car, But still got that 650![img]/phpBB/images/smiles/icon_lol.gif[/img]




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Is the 650 the only size that holley made the SB in? If so then I guess we can rule that one out because I was hoping to get a little more CFM than what I have now, but with the smaller primaries of the SB/Q-jet type carb.
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If I were you, I'd change the intake first and use the same carb. My guess is you'll be pretty happy with that change alone

Isn't your Edelbrock already a spreadbore? Yeah, I know it's not like a Quadrajet, but I thought they used different sizes...
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Nope, the Edelbrock performers are square-bore, they're all the same size... although I think the fuel metering system is similar to a Q-jet.
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They made a smaller SB, a 450 I think. How many ponies is that baby pushin'. Do you want vac or mech. secondaries?
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The Bronco is probably only about 300hp, it's got stock heads, a mild cam, and performer intake, stock 8:1 pistons, tri-y headers and dual 2.5 exhaust. It will be replaced with a 9:1 short block with ported heads (lots of work on the exhaust side) and a little more agressive cam in the future, looking for around 400+hp and LOTS of torque. I like the feel of mechanical secondaries, but I could live with vacuum secondaries on the q-jet for the increase in mileage from the Q-jet. I've been looking on eBay and it looks like I can score a Rochester for dirt cheap, in either the 750 or 795cfm flavors... even rebuilt ones... but I'm scared that they might have some weird vacuum hookups or some other crap for '70s and '80s emissions stuff that I don't have. Is this something I should be concerned about? I just wanna hook up the fuel line, the electric choke, and maybe fab a little on the throttle linkage if necessary, do I have to worry about buying one that has any weird emissions hookups on it that won't run right disconnected?

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'86 Bronco fullsize, 460, E4OD, 6" lift, 35" BFGs, 4.56 posi

'85 Ranger, 340hp 289, T5, Cobra wheels, 245/45/ZR17, 4.10 posi 7.5"


<font size=-1>[ This Message was edited by: Motorhead on 3/3/05 11:05am ]</font>

Along with my mustang I also own a 64 pontiac station wagon with a 389. The pontiac guys use quadrajets a lot in the big poncho motors for their low end power, milage, and they are even used for some very fast street cars (I know of an 11 second wagon that uses a quadrajet). I use a demon in my mustang although that get revved alot and I like the top end, although the low end is not bad at all. The family truck has a quadrajet (84 chevy) with all of the smog stuff and it is tuned lean from the factory, lots of low end though. I have also heard that the quadrajets are easy to tune as well.

Oops I was doing some reading on the web and uriah you're partially right... the edelbrock 750 has all 4 barrels the same size like I said, but the smaller ones like the 600 have the same size secondaries as the 750 but smaller primaries.
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