The Stovebolt Site Forums The Shop Area Engine Shop 250 engine w 1bbl carb -- can use 2bbl?

Both of my 250 engines have 1bbl carbs. I am wondering what common ( not special ) 2bbl will or can be used. What do you folks recommend. Thank you.
Slider

There are no 2bbls common to the 250. The exception is the later 250s with the integral head came stock with a 2bbl. Hope that helps.

Larry

did Pont, olds, or buick make a 250? did they have 2bbl intakes? would those work on chevy? I am also trying to seperate 250 fact from fiction ya got me curious too slider

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.

Again There are no 2bbls common to the 250 in any GM vehicle made in the USA. The exception is the later 250s with the integral head came stock with a 2bbl. I did forget one other exception. There is a 2bbl manifold that was made in the southern hemisphere. I've seen pictures of it, I have not heard of anyone getting one up here. Evidently GM did develope the L6 a bit more for south America. There may even be another head for 250 down there.

Beltfed is right you can either use a 2bbl adapter to the stock manifold or an adapter on a Clifford or Offy manifold. If you have the tools you make an adapter plate to bolt to the stock manifold for a 2bbl. You have to flatten the top of the manifold, hog out the stock hole, and make a gasket.

Larry

If you don't have the integral manifold head, you could use a manifold from a late 292. They had 2 bbl carbs- Rochester 2SE progressive type. It is more or less a Q-Jet primary and secondary. Not a bad carb if tuned right and kept clean.

Longbox55, I've never seen or heard of any other manifold other than the Integral head and the south American that used a 2bbl. I have heard that the 2SE is a nice carb, it is also what they used on the Integral head. Could you give a little more detail as to what late model 292 used that carb other than the integral head. I sure would like one for my 292. :confused:

Larry

Longbox55, Thanks, did i understand you to say that late 292`s have a two (2) bbl intake manifold? That would be cool. Can you verify that for me? Thanks. This looks like a good topic we have going here

I think I may have goofed. I could have sworn I saw that info on the 2 bbl on a 292 in a shop manual, but so far all the spec books I've checked say single bbl on 292. I also seem to recall the shop my dad used to work for had an '80-'82 (?) C20 that had a 292 with 2bbl. I'm going to look around some more, see if I can find that manual that I saw it in.