claybill Posted May 6, 2008 Report Share Posted May 6, 2008 i have been using a 2 bbl carb adaptor on my 218 test motor. with a stromberg WW carb. both excellent shape but i prefer the offy dual B&B set-up. i will offer both for sale ..reasonable. i also have the intake manifold widened to allow for the larger flow.. anybody interested? claybill Quote Link to comment Share on other sites More sharing options...
Johnny S Posted May 6, 2008 Report Share Posted May 6, 2008 Why do you prefer the Offy dual B&B? Does the 2 bbl work ok? Quote Link to comment Share on other sites More sharing options...
claybill Posted May 6, 2008 Author Report Share Posted May 6, 2008 i cant seem to get the stromberg to idle down smoothly. although it has very good and crisp throttle response. the aluminum adaptor is professionally made and beautiful. it is noticeable that the stromberg is a bit quicker revving....but cant get it to idle right. changed plugs...i sense a miss in the motor at this point too. anyway i like the 'dual' look. carter b&b's are easy for me with all my parts etc. anything else? bill Quote Link to comment Share on other sites More sharing options...
Johnny S Posted May 6, 2008 Report Share Posted May 6, 2008 Any idea on how much air the 2bbl flows? Does it have a CFM rating? I've been thinking about trying a Weber 32/36 but don't know if it will match up with the flat head very well or not. Quote Link to comment Share on other sites More sharing options...
claybill Posted May 6, 2008 Author Report Share Posted May 6, 2008 i have absolutey no idea on those figures..... however the 55-6 -7 ?? plymouth flatheads used a 2bbl carb as standard, i believe. bill Quote Link to comment Share on other sites More sharing options...
48mirage Posted May 6, 2008 Report Share Posted May 6, 2008 If I am looking right that Stromberg WW (common to late 60's GM pickups) was standard equipment for the 351 and larger engines. You have too much carberation for your 218. Find a smaller 2 barrel. I use a Holley 94 on my 230 cubic inch D30. Quote Link to comment Share on other sites More sharing options...
bobby horne Posted May 6, 2008 Report Share Posted May 6, 2008 .............This intake came off my 1956 Dodge engine....A 305 Chevy Carb fits, but I may have to rejet to match my Dodge engine..... Quote Link to comment Share on other sites More sharing options...
bobby horne Posted May 6, 2008 Report Share Posted May 6, 2008 ............These adapters are on ebay sometimes, but I would think a 2 barrel shrinking down to a 1 barrel intake would be very restrictive.............. Quote Link to comment Share on other sites More sharing options...
claybill Posted May 6, 2008 Author Report Share Posted May 6, 2008 you have to do some grnding on the intake opening to match up the adaptor. i am using it on a 230, not a 218 as i mentioned in error. the holley 94 does not match up to the bolt pattern of the adaptor, as i recall. the WW was recommended. the adaptor seems to be machined to adapt to the flow pattern ..but you have to match it up with the intake hole. bill Quote Link to comment Share on other sites More sharing options...
48mirage Posted May 6, 2008 Report Share Posted May 6, 2008 When deciding what size carb I needed I did some researching and found a formula for calculating the maximum size of carb to use based on engine size and some other data. I have one of the largest Holley 94's (1 1/16" venturi's) and it is on the border of almost being too big. Like you excellent throttle response but I have my idle screw backed off so that it just touches the stop. The idle is just a little above the tuning numbers. I might be able to slow the engine down a little with a change in idle jets but in my case the idle is only about 50 rpm high. For my adapter to the single barrel manifold I had a local machinist make it using gaskets as templates. Bobby Horne in his reply was worried about the restrictions. If there are no sharp corners or abrupt direction changes in the flow the net effect in a speeding up of the fuel/air mix through the narrow part of the adapter. I would think this would help with the mixing. Quote Link to comment Share on other sites More sharing options...
48mirage Posted May 6, 2008 Report Share Posted May 6, 2008 Try this link to size the carb that works best for your engine. http://www.csgnetwork.com/cfmcalc.html Quote Link to comment Share on other sites More sharing options...
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