Dumb Carb Question

[schaferstephen]

FINALLY ordered all my goodies for my 250... I'm going to model my engine after 62Ranchero's, as far as the 300 connecting rods and custom pistons. The only difference is, I want to put a 4bbl on... Hence my questions.

I have an opportunity to get a 4bbl Edelbrock 500cfm for a great price. Will that mount up to the Holley adapter? Also, what are your opinions on a 390 Holley 4bbl as opposed to the Edelbrock? Thanks guys.

 

[rbohm]

well, unless you are using the classicinlines aluminum head, you wont be able to put a four barrel carb on your 200, without a lot of modification.

 

[schaferstephen]

Sorry I didn't clarify - I ordered the head from Mike last night, I am going to go with a 2bbl carb. Just out of curiousity though, what are yall thoughts on 2 vs 4bbl? I know all the flow rates and carb calculations. I'm just curious about personal experience.

 

[wsa111]

First of all what year vehicle do you have? 67 & up have a much wider distance between the spring towers. Clearance can be a problem.
The 4 barrel will flow a lot more than any 2 barrel.
The Holley has twice the tune ability than the Edelbrock. However the Edelbrock-AFB is very reliably due to its design.

 

[rbohm]

actually the edelborck is the more tunable carb than the holley is unless you get aftermarket metering blocks for the holley. either way though both carbs are good ones to run. the edebrock uses an air valve secondary, which uses total airflow to regulate the secondaries, where as the holley vacuum secondary carbs uses the speed of the air flowing through the venturies.

the edebrock has a 500cfm four barrel, the holley has a small 390cfm four barrel. in the vacuum secondary the next size up for the holley is the 570cfm, then the 600cfm.

 

[bubba22349]

Actually Holley also has a 4V that's 465 CFM too I have one and looking for another.

 

[wsa111]

actually the edelborck is the more tunable carb than the holley is unless you get aftermarket metering blocks for the holley. either way though both carbs are good ones to run. the edebrock uses an air valve secondary, which uses total airflow to regulate the secondaries, where as the holley vacuum secondary carbs uses the speed of the air flowing through the venturies.

the edebrock has a 500cfm four barrel, the holley has a small 390cfm four barrel. in the vacuum secondary the next size up for the holley is the 570cfm, then the 600cfm.

I can modify a stock Holley metering block within 95% of the features of an aftermarket metering block.
The Edelbrock is just a takeoff of the old carter AFB but with improved primary venturi's.
Put it this way it takes me 3 times longer to tune an Edelbrock carb.
You need a wideband A/F tester to properly fine tune both. Bill

 

[rbohm]

Actually Holley also has a 4V that's 465 CFM too I have one and looking for another.

very true, but since i referenced vacuum secondaries, i ignored that carb.

 

[xctasy]

4-bbls are easier to get a good idle from. For coil spring over a arm X shell uni-bodies, they are harder to package, even with the Classic Inlines intake. You just have to get serious, and make the changes to make it fit.

The vac sec 4150/4160 series carbs are very easy to tune, you have to set the secondaries open a little, and follow Dave Emanuel's guidelines, but they reward you with no problems with on idle and off idle holes when in reverses or when picking up at lights. 2-bbl 2300 series Holleys suffer reversion problems that can be fixed by using the tools Bill has at his disposal. They aren't calibrated for I6's, so they need a good deal of reworking. What Bill does is right down the line on pages 76 to 82 in the Holley Performance book by Dave Emanuel, but with all the air bleed, PVCR and metering issues worked out form a guy who uses a big carb on his 200 Mustang.


If you know your stuff, a 500 cfm Holley with 1.375" chokes and 1.6875" throttles will work really well. Its easier to tune and fit a 4412 series Holley with the parts available now. Going to a smaller carb like an Autolite 1.08, 1.14, 1.21 is pointless when there is so much good info on making the bigger 500 cf carb work.

 

[schaferstephen]

Before I go any further... I have a 65. Is it even possible to get the 4brl in without cutting the towers?

 

[62Ranchero200]

Just to clarify, that's a '65 Mustang, right?

My experience is with Falcons and Rancheros, so someone else will have to chime in here. On my '62 Ranchero, there might be enough room for a 4 BBL without cutting any of the shock tower sheet metal away - I'd almost have to try it to find out, it's that close. But so far I'm happy with the performance of my Holley 2300 2 BBL so I have no plans to change that.

Thanks
Bob

 

[rbohm]

Before I go any further... I have a 65. Is it even possible to get the 4brl in without cutting the towers?

it should fit, though with little overall clearance.

 

[schaferstephen]

Yes it's a 65 mustang... Probably time I edit my signature. lol