I need input from the guru's. I have a 1974 F250 390/C6 2X4 Camper Special. My carb is in need of re-building or replacing. It had a Carter that I am pretty sure I ruined by my attempt at re-building. Anyway I have a Holley that used to be on it but leaks fuel. My question is, is it worth having the Holley re-built or should I buy new.
I don't want to spend any more than I have to on this truck but I would like it to work. Now the guy at Auto Zone said he has a new replacement carb made by National that is I guess a copy of the Holley? Any input would be appreciated.

 

Need a hair more info...

Is your 390 a factory 4-barrel with its cast iron intake?

 

Well it is a factory 4 barrel cast iron intake. Don't know what carb it had originally and it wasn't always a 390. But for all intent and purposes it is a stock 390.

 

Ok... so it's a 4 bbl.

There are typically three choices - an Autolite 4100, Edelbrock, or Holley. But I'll throw in the new series of Demon carbs and Summit Racing's Holley clone. Then it depends if ya want electric or manual choke, vacuum or mechanical secondaries. For a daily driver, I suggest a ballpark range of 500 cfm to 650 cfm. With that said, it's up to you whether a carb is tuned for mileage vs performance.

For mileage & ease of use stay with vacuum secondaries, - look into an Autolite 4100 (1.12 stamping), Edelbrock Performer 1406, a Holley 4160, 670 cfm Holley Street Avenger, and the Summit clone.

For performance, an Edelbrock Performer 1405, 650 double-pumper, or Demon's Road Demon.

'never heard of National. They must be the house brand or with whom Autozone contracts their rebuilds.

For these trucks, I like the Autolite 4100 and the Edelbrock 1406.

 

Might want to think twice about the Demon carbs, as last I checked, they're not in business anymore. I have a Demon on mine, but called for some information and was told they're not in business anymore. That was a kick in the crotch for me, as I have a Demon, but I've been told that a lot of Holley parts cross over to Demon, so that might help in the long run.

If someone has any new information about Demon being back in business, I'm all ears, but that's the last word I had.

 

On my 400 I have the holley street avenger 670cfm. electric choke, vacuum secondaries, I love it. Never had to tweak it at all, ran right out of the box.

 

Then happy days are here again for ya. The company changed ownership and production is back up along with new products... apparently with stricter quality control.
Demon Fuel Systems

 

You have no idea how happy that makes me.....I've been adapting Holley linkage bits to connect my Demon to Buford, and it's been driving me a little goofy. I tried a Lokar kickdown cable, and the bracket for that gets directly in the way of the throttle cable. So, I'm going to go back to the original kickdown rod (as I have it, and it's all powdercoated black anyway), and use an extension kit to adapt it to the carb. I just haven't figured out an extension on the carb so I can connect the stock throttle cable, but it'll come to me.

I'll have to check out their site to see what new goodies they have! Thanks for the update.

 

You're welcome.

Click on the "Info" tab on their happening since their plant closed back in Feb. 2011.

Btw, I was looking at their 525 Road Demon Jr. and they will apparently be available with a Ford kickdown linkage... Maybe it'll retrofit to what ya gots.

 

I've got a performer RPM intake I want to put on my 460 when I get headers for it, and I'll be replacing the carb. I have an edelbrock performer 600 cfm carb (I think its 600) that was on the engine with the intake when I got it, but I'm thinking the 460 will need more fuel than that. I've noticed both holly and edelbrock make specific off road carbs that are designed to operate on steeper angles, and I'm thinking about buying one. The holly is 770 and the edelbrocks are 650. I don't know if I'd be better off with one of those or with a larger street oriented carb. My truck is pretty much off road only, for work and for play. I've still got the stock autolite on there and its running, but I think its developed a metering problem as its running extremely rich. It always has, and its got progressively worse over the past year.

 

Yeah, that might work, but I'm betting I can make some combination work of the Holley parts that I've ordered in. Mine is a Speed Demon 750 with the annular boosters, so that constricts it down to roughly 725 cfm, but it's perfect for my plant. I'm just glad they're back in business, should I need a rebuild kit, or any other bits and pieces for the carb. I didn't want to have to start from scratch and try to match another brand carb to the situation. Anyway, thanks again for the info!

 

Thanks for the info. Last question. How do you guys feel about having a carb re-built? I already have a Holley but not sure about how good re-builds are.

 

If you've done your best to rebuild and tune it and it is still giving ya problems, save yourself the headache and pony up for a new one. Sometimes buying peace of mind and taking it out of the equation is better than having that nagging feeling ya got a lemon of a rebuild.

FYI, about the "cheapest" new carb is Summit's Holley clone... around $260.. and it uses Holley replacement parts.

Good luck with your decision.

 

You can get factory rebuilts from holley and even edelbrock, too. I'm not sure if they are old carbs they rebuild, or more likely just "refurbished" customer returns, but they are like $100 cheaper than new.

 

National doesn't make carbs they are a rebuilder. They have rebuilt carbs for all types of cars and trucks. They even have rebuilt Holley and Edelbrocks. I put a rebuilt 2150 on my truck... looks and performs great.