I kept my 2 barrel. the primarys are bigger than going to a small 4 barrel. to me the fuel milage is better, and i have a cam, headers etc. also a 304 is a small v8, so you don't really need a 4 barrel. however (I like talking out of both sides of my mouth) if the 2 barrel needs repair or doesn't run well and the 4 barrel is running great well there's your answer!
about the 304 I cant realy tell you but I will say that my buddy and I have verry similar jeeps both with AMC 360's and T-18's with granny gear and the same gearing in the axles the only differances are that he has lockers in both axles I dont have any, he is running 37 x 12.5 and I am running 35 x 12.5 and he has the 4 barrel, I think it is a 750, I have a stock autolite 2 barrel and he gets allmost twice the fuel millage that I get. So I would say 4 barrel for sure, I know I am looking at that being my next buy for my Jeep.
My newly rebuilt 304 got its final tune up today. . . .it runs sweet, Holley 670TA, 40 over, balanced, torquer cam, valve springs, performer intake, edelbrock shorties. Now we get to do suspension. . . . . .can't wait.
I had a 327 with a 4 barrel and it ram like a champ with an edelbrock manifold! Is your manifold for the 4 barrel a performer or performer rpm by chance? If it's the rpm there is no doubt in my mind that the 4 barrel would work better
A 750 is way to much carb for a 304, 600cfm is perfect. I have a 600cfm edelbrock on my 78 F-250 with a 351 cleveland. It runs nice and gets 10 mpg.
I agree that a 600 is perfect, but if he's running a dual plane intake there is vertually no such thing as "too much carb". The air doesn't die the way it can entering a single plane manifold if you run a carb that has too much flow.
If the 750 has mechanical secondaries, dump it. It is too big and is designed for high RPM use.
That being said, a properly tuned, vacuum secondary, four barrel of the proper size will almost always out perform a comparable two barrel. This is because the primaries are generally smaller on the 4 bbl. This gives better low end power and economy while the secondaries can be enriched for more power under WOT and high RPM situations. 500CFM should be about right for a 304 running under 5000RPM's.
I was thinking about switching out my Edelbrock Performer 600 for a Holley Truck Avenger 470, I'm guessing this would be a good switch, or should i get the TA 670 so I could have alittle legroom incase I wanted to swap in an AMC360 in the future?
To all that have responded, I will say that neither of the 360's are stock, the one with the 4 barrel I know is 60 over and I believe crank and cam have been changed, the carb does have the small front two barrels. And I am not trying to sway anyone from a 600, I myself am looking at a 600, I was just giving a kind of apples to apples comarison from two like vehicles so that he could go on that.