Intake manifold and carb

[CommanderToasty]

Edlebrock maybe for an R-1? Are there any improved performance intakes or carbs for the stock 289?

[Gunslinger]

An Edelbrock carb is an updated AFB and would be an improvement...if your AFB needs rebuilding or replacing. The best Edelbrock for an R1 is the 500 cfm model with electric choke. Since the PCV threads into the base of the AFB and the Edelbrock isn't set up that way, a threaded inlet would ned to be drilled and tapped into it. Rather than the rear of the carb, it's better to install the PCV into the front as it works better that way.

The electric choke is better than the old bi-metallic spring choke, it takes some minor wiring to a switched 12V source.

To switch to the Edelbrock would necessitate a change in the air cleaner base...the original AFB has a 4 1/2" bowl opening than the 5 1/8" opening of the Edelbrock or other modern carburetors. An appropriate base is available from several of the Studebaker vendors...with or without the chrome top. You could keep or sell the original base to offset some of the costs.

I like Edelbrock products...they make great stuff.

As far as an intake, you're pretty much stuck with the stock cast iron unit...some aluminum units have been made but I understand they require a great deal of machine work to make them really usable. Having your stock intake gone over by an experienced machinist to eliminate the roughness on the interior and smooth out airflow will get all the performance out of an R1 available. To get more would require some serious head work.

If you would find one of the aluminum intakes floating around (and can afford the cost), by all means get it. But...don't expect an increase in performance that's noticeable. Given equal design and machining, the air doesn't care whether it's aluminum or cast iron it's passing through. What you gain with aluminum is less weight (a good thing), and somewhat better heat transfer. Whether that can make any real difference in performance will depend how well the engine is tuned.

[CommanderToasty]

Thank you for that very informative response.

Edelbrock makes carbs in the 750 CFM and much higher range so I am assuming you believe that the little bores of the 289 just can't inhale enough to make it any benefit going over 500cfm? Wasted air that would be leaned out? Do you know how many cfm the stock carb is?

Another consideration is the amount of air surface available for collection if I maintain the stock cover. Using a new base plate with proper diameter for the new carb and using the stock cover - which I would like to do - may not increase the surface area of the filter and may not allow the 500cfm carb to breath well enough. Thoughts?

Thanks again.

[Gunslinger]

I'm no carburetor expert...actually I think carburetors are voodoo. I do have a somewhat basic understanding that there is a formula for determining the proper airflow for an engine displacement. You use a carb capable of too much airflow and you have low rpm stumbling on takeoff. It would take a fair amount of re-jetting a 750 cfm carb (of any manufacturer) to avoid that...and you end up with a lower cfm carb, so why not get the proper size carb to begin with. A carb only can use the extra cfm at wide open throttle anyway and a 289 engine simply doesn't have the capacity to suck in that much air without radical changes, if at all.

I wouldn't worry about the size of the air filter...it can probably flow more air than the engine can use anyway. Studebaker designed in an appropriate air filter to satisfy the needs of the induction system (and clear the low hood). What you could do is buy a K&N or similar design air filter of the same size...they will definitely flow more air than a paper filter. Some will tell you to avoid that type of filter as they claim they don't filter well and can allow contaminants into the engine. I use K&N on a couple of my cars as have millions of other people and I've not heard of any problems. They are pricey though but don't require replacing if you maintain them properly.