So I have a basically brand new Edelbrock carb that I took off my 300 six on my f150. I was thinking of putting it on my f250 with a 351W H.O. but I believe the motorcraft/holley that is on there is a 600 cfm. Would the edelbrock be too small for this engine?

 

It may work, but you're not going to see the full potential of the engine at that size. Think restricter plate. The 351s love anywhere from 600 to 700 cfms. On my old truck, with 351, I had an Edelbrock 600 on it. Ran good all the time. Had a 700 laying around and just for the heck of it one day, threw it on. Completely different animal. Went back to the 600 to tame it back down. All the online calculators I tried say a 500 cfm is perfect for that engine, but Fords tend to like a bit more.

 

Thanks for reply. I agree partner a Holley 600 or Eddy 600 would be the ideal carburetor for this engine but I hate to see a good carburetor go to waste. The original carburetor is leaking fuel from the bowls and looks like it needs a rebuild.

 

Why not try it? Can't cost much.

 

I am going to give the Edelbrock a try but before I went ahead and got all the necessary things for the c6 tranny to work. I figured I would ask and get someone's opinion first.

 

It depends on how you are going to drive it. For a DD a smaller carb can give a crisper throttle response and better fuel economy. That's because the smaller venturi give a stronger vacuum signal at the same CFM, and that makes tuning more precise. But, you do give up some top-end power.

Let's put this in perspective. Most 351's came with a 2bbl 2150 carb with 1.21" venturi, and that carb is rated at 351 CFM - at 3"" of vacuum. But 4bbl carbs are rated at 1.5" of vacuum, as explained here: THE CARBURETOR SHOP / Carburetor sizes and CFM. And, as stated there, to convert a 2bbl rating to a 4bbl rating you divide by 1.414, which gives 248 CFM. In other words, your Eddy has twice the CFM rating as the normal 2bbl that came on these trucks. And yet is is progressive so you have the small primaries to run on normally, and the secondaries when you want a lot of power.

Again, it isn't going to cost anything to try, and you may really like it. On the other hand, if you want all-out top end power then you'll need to look elsewhere. But, your daily driving will pay the price in that case.

The carb that can provide the best daily driving as well as max power has been a quest for a long time. That's why the Quadrajet and ThermoQuad carbs were designed, and their little primaries and huge secondaries did do a good job of meeting both goals. And today"s Street Demon carries on that theme, having chosen the best bits from both of those carbs. But, maybe you don't need max power and will be happy with the 500's performance. You won't know until you try.

 

Unless you plan to have the engine above ~3500 RPM on a regular basis, I'd bet the 500 CFM is more than sufficent.

 

Oh no I don't plan to hot rod this truck. It will be my daily driver in the winters and whenever my dad wants to haul big loads that my 86 F150 can't handle. Believe it or not my F150 with a 300 six is my hot rod haha.

 

If you don't make the engine scream, you'll like it just fine. I've swapped just such a carburetor in place of a Holley/Motorcraft on a 5.0 engine and was surprised to get a bit better gas mileage when commuting. I bet you'll see an even better gain. I've become a really big fan of throttle response over the years. I expect you'll like that too.

 

500 CFM should be plenty, it's a pickup not a race car. In fact, the 500CFM should give better throttle response, better drive-ability and hopefully improved MPG over the 600 CFM and above.

 

Oh yeah definitely I am too. Throttle response is awesome. I did the tune up the couple weeks ago and could hear the difference already but I also added a mallory ignition box so that could have been helpful too.

FordFETruck your truck is beautiful man. I've seena couple of your videos on YouTube. I like your floor mats! Haha

 

Thanks! I've had a few people say they like my floor mats lol. There's a company name on the back of them I'll have to look at it and post it. They're pretty old, they were in our Galaxie when we bought it in 1999.

 

Awesome! Please I wouldn't mind getting some if there still available!