Need some advice on intake and carb for 4.8L stroker

[CobraMarty]

Carb will only flow fuel proportional to the airflow thru it, bigger carb doesn't mean more fuel, bigger jets- yes more fuel. IIRC for max power you want/size a carb up to 10-20% larger than engine cfm requirements(but that might be for a carb rating into a roots s/c). That is why you are seeing 390, 450, 470, 600 cfm carbs. For all out performance you can't go wrong with a double pumper but not the best for the street. Vac secondary 4 barrels are better for the street, the 38/32 weber will have the best economy and driveability on the street but will be giving up power at wot.

The math is also assuming 90%VE which is probably high for the jeep engine and 6000rpm which is also high.
289x5500rpmx.85VE=390cfm.

Dual plane I6 manifold looks and seems dumb- the idea of 'splitting' a runner, on a V8 yes DP.

So... be realistic about your engine build and rpm. Get a 38/32 weber and intake and also a 450 double pumper and 4 barrel intake and try them both and sell the one you like least. ?more street manners or more race manners.

Be different and use the 38/32 weber and add Nitrous!

[pityocamptes]

Thanks. I had a weber 32/36 on my original amc 258 and never really liked it. If you had to pick a a brand and model, would you go with a holley or edelbrock? Thanks again...

Contacted edelbrock, they are recommending part #1801, still waiting to hear back from holley and their recommendations. Thoughts on the 1801 and offroad capability?

[I6FAN]

Personally, I think 600 cfm carbs on an inline six is a little too much unless you are racing. The larger venture size will see a decreased velocity, and that in turn will result in poor atomization and throttle response (might affect longevity).

I think I remember hearing that the Clifford 4brl intake had some fuel distribution issues, but not too bad..... The Offy intake is called a Dual-Plane, but it is not a dual plane in the sense of a v8 dual plane which groups intake runners by alternating-cylinder-breathing/firing order (v8 fires every 90 degrees, so by alternating it's grouped by every 180 degrees). Totally different, although named the same, the Offy Dual Plane has a partition in it that allows for two primary barrels of carb to breathe through during normal driving, and then the secondaries of the carb actually have their own with the merit of this being better driving response.

You see a lot of Ford 300's with the Edelbrock 500 cfm which is not that far off from a Jeep stroker engine. If your fixated on a four-brl, my choices would be either Edelbrock 500 cfm, Holley Truck Avenger 470 cfm, and I would look into the Barry Grant Road Demon 525 cfm (nothing bigger than this one, and BG has mixed reviews). The Holley TA 470 has the off road drivabilities built into it, so that would be a plus.

As some have suggested, Fuel Injection would be an excellent option, and there are a few on this site that can re-program the factory ECU's to better match engine upgrades. Before this there was a little left on the table, but this gap seems to be closing.