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Technical Area => Upkeep and Performance Hints => Topic started by: JohnTwist on August 06, 2021, 01:51:22 PM

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Title: SU Carbs
Post by: JohnTwist on August 06, 2021, 01:51:22 PM
I currently have a Weber carb on my 1980 MGB. I am thinking about installing SU carbs. Have heard you talk about them. Can you suggest exactly what twin carbs I should look for, how much to pay, maybe suggest where I could get a pair? Are rebuild parts available? Donít care too much for the carb. It does the job but would rather have the SUís.

My advice, if you want SU carburetors (and why would you not?), is to got with the HS carb used 1962-1971.  The HIF carb used 1972-1974 (and on the home models) has a float bowl at the bottom which makes them all but impossible to service in situ.  The HS and HIF use different thicknesses on the mating flanges of the intake and exhaust manifold. The HS is 1/8" thicker. 
I would change your exhaust, whatever it may be now, to the factory manifold and front header pipe.  It's the absolute best for the exhaust flow (double Y construction), and it fits and, properly fitted, doesn't leak.  Headers are not as good for the air flow, they're hot, and they're noisy -- AND they usually leak.  SU carbs look better, too.

So you'll want a "kit" with everything from the manifolding and front exhaust pipe to the carbs, linkages, cables, and air cleaners (conical K&N).  The only shop I know that could put this together and get it to you relatively quickly would be Sportscar Craftsmen in Arvada, CO.  Talk to Paul.  Price?  You'll have to ask him, but less than a supercharger!  Paul's email is in the To: address line above.

At the same time you'll want to get a new distributor conforming to the Lucas 40897 original 62-67 advance curve.  You can purchase one of those (or have yours rebuilt) from Jeff Schlemmer at Advanced Distributor in MN or Rob Medynski at British Vacuum Unit in NH.  All three of these concerns have websites, emails, and phones.

Hope this helps!
John H Twist
University Motors Online
100 East Beltline Avenue SE
Grand Rapids MI 49506-2410
Cell  616 307 6737

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