SU carbs on 1500

Well I just received my 1 1/2" intake manifold for my 1500.  And today I 
bought a pair of pretty good rebuildable HS6 SU carbs to bolt onto it.   They 
probably have very few miles on them, relatively speaking.  But they are 
pretty gunked up.  The carbs came off a '67 MGBGT and have blocks probably 1 
1/2" - 2" thick.  Will the blocks be needed when I mount the carbs to the 
manifold in this usage?

--David C.