I'm not sure what the years are on your 250's, but I'm sure someone makes a 2bbl to 1 bbl adapter plate you can use. Not to take away from anyone who wants to keep their ride orginial as I like them alot. On my 250 I just didn't want anything more to do with the old Rochester 1 and 2 barrel carbs. Just look at the many past posts, including mine, on this site and you'll see what I mean. The reason I first showed up here was trying to deal with two old "B" model Rochesters that cost me an engine rebuild. I ended up putting a 390cfm Holley 4-bbl on top of a Offy intake and the difference is unreal. It still gives me a great deal of pleasure to be on a rod rod with my buddies starting out in the morning from a motel. My 250 roars to life with a bump of the key when their 350 sbc grind away for several plus seconds to bring them to life. Another great thing is when you are showing off your engine. You will get many onlookers calling their buddies over to take a look at the "hot" 4-bbl setup setting on 6-banger.
