Holley help

[groho]

OK, I've worked on Quad, Carters, Edelbrock carbs, but never a Holley. After doing some research regarding the best carb for autocrossing, I found my Edelbrock wasn't up for the task. Knowing it works, I'll use it to break in the motor and camshaft, and then move to the Holley. The motor is a 302 bored .30, AFR165 heads, Weiand dual plane intake, Comp Cams XE268H 230dur, 510lif, built C4 with 2400 stall, 3:25 trac-loc. My intent was to mirror aspects of the Holley offroad avenger. To my surprise, my awesome brother handed me a 4150, center hung, 600CFM, vac sec! This is exactly what I wanted for my base line carb. I was intending to keep the jetting fairly stock given the motor c.u., but add jet extensions in the primary and secondary, and change to notched road racing floats in both bowls, plus add a QFT adjustable vacuum secondary kit. The last missing piece is the one-piece cross over vent tube. First, am I on track to build a workable Holley for autocross and street? Second, can someone give me an idea for a cross over vent tube given the vent tubes are part of the casting. They come very close to the bottom of the air cleaner lid. Ideas? I noticed this was different then the flush cut vent tubes using brass. Is this casting of the older Holley's? I found the Holley spec sheet to help me identify the factory installed jets, power valves, etc.

[groho]

BTW, the jet extensions in the primaries, was to overcome the hard deceleration under braking. I realize this is not normal thinking, but thought I'd give it a try.

[Derek@ModernSpeed]

It's a great thing you didn't start with the truck avenger carb. I'm not sure how the jet extensions will work in the front, but the rear is a good idea. Wedged road race floats are a necessity. If you are looking for a vent tube similar to that of the truck avenger carbs, good luck. When I worked at Holley, it was against the rules to sell that, or even send one out to help someone. There was a company selling them on ebay, however I believe Holley was trying to get that stopped. If you can't get one, a piece of fuel line running vent to vent with a hole in the top (center) will work. It has for years. If you post the List # on the choke tower of the Holley, we will know more about what you have to start with.

[groho]

the list # is 80145. I noticed the kit on ebay you reference, not keen about buying stuff on ebay. I was hacking in the garage and actually bent an identical vent tube using 5/16 thick walled aluminum, worked perfect, until I realized my existing vent tubes are part of the casting. This prevents getting the crossover low enough to clear the air cleaner lid. So what's the preferred approach? Cut the cross overs flush to the main body and then install the cross over? Is there a more preferred carb for autocross? Why a carb? carb vs EFI = free vs $3000. I understand EFI is better, but that's a long term goal due to the cost.

[Red67Mustang]

Skip the jet extensions on the primary side. The intended logic of compensating for deceleration is flawed since you're not on the gas during deceleration. Heck, my Holley HP EFI even cuts off fuel during engine braking. I think you'll find jet extensions on the primary's would only give you trouble; uncovering the jets on hard acceleration.

[sam 74]

With extensions on the primary you'll starve for fuel on acceleration.

[formula jg]

Will this work for you?



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