750cfm 4 Barrel or 3x2

I'm sitting at a cross road I have a 401 with a TA-25 cam paired up to a SP400 in a 1950 Chevy Pickup. I currently have a 3 deuce setup with progressive linkage on the engine. I also have a single 4 barrel 750cfm Edelbrock. Would there be a large performance difference between the 4 barrel and 3x2 on a dyno. They both have about the same amount of CFM's at WOT

 

IMHO, other than "Eye Candy" performance will be better & easier to tune with the 750.

 

I could see distribution being better with the 3x2

 

If you are worried about power, I'd be more focusing on cylinder head work, intake work, more aggressive cam using the overlap strategies to your advantage.
Either induction has more than enough cfm to meet the need.

 

^^this

Ease of tuning, the single 4v carb.

CFM requirements, good on either.

All good advice.

 

In actuality distribution is WORSE with a 3x2 which is inherit to the design on a "Nail". It's been proven in the past by some others rather than myself.

 

With the center runners being paired , yea that would make sense

 

I doubt if there would be a major significance in power between the two. If either one had an advantage it would be the single 4bbl. but the cool factor with the 3x2 setup is leaps and bounds higher than the single.

 

I was thinking of more traditional engine designs, and the "Nail's" are another animal, so makes sense. Thanks for the correction!

 

Also don't forget the odd firing order which starts on the right/passenger side as No. 1 1-2-7-8-4-5-6-3

 

If you change #2 to #1 you would have 1-8-7-3-6-5-4-2, which would be a 4/7 swap firing order vs the more traditional firing order that the General used with multiple brand engines. Looks like Buick invented to 4/7 swap before anyone!

Interesting!




Derek

 

far and away,,,, the single carb is better.... this plus a cold air pkg... coupled with a doc dual plane mod ...would be a good solid increase of power..... keep the heat in the intake......

 

So I decided to swap the 3x2 out for the 750cfm 4 barrel. The shop handling the job is stated as one of the best in our area but they have me worried when they called and said the 750 was to much carb and if I could get a 500cfm I told them no and that Russ Martin advised me to put a 750 on it.

 

Probably just trying to sell you a carb?
I wouldn't worry about them bolting on a simple intake, that should be pretty easy

(BTW, if you have the emissions tuned 750 you might have tuning issues)

 

I don't know if it's the emission tuned version it's a new Edelbrock 1407 750cfm

 

HMMMMMM ,,,, if 1 seven fifty cfm carb is too much carb... why did buick put dual carbs on a nailhead :Brow::Brow:

That shop is not in the know about nailhead buick engines.... nails have always liked more carb ..... :grin: just make sure the carb has vacume secondaries on it... that way the rpm's are up when the back barrels come in....:idea2:

 

I did a back to back track test of a 750 Q-Jet vs. an 800 Q-jet, and the car picked up a tenth or two, I wrote it up on the board here some time ago. The carbs were set up and jetted identically. These cars just like big carbs, so I'd try an 850 if you were set on going square bore.....

 

They are not in the know about many engines that like large carbs, or were erring towards owner tuned maladies.

 

Aggravation is equal to the square of the number parts in the assembly. The aggravation factor of three carburetors is nine. The aggravation factor of a single carburetor is one. Take your pick.