SU intake Manifold


Asked by Frisba Jul 31, 2013 at 11:05 PM about the 1978 Triumph Spitfire

Question type: Car Customization

I'm swapping from a single Stromberg to twin SU's. What is the big hole for in the top, left
part of the SU intake manifold? It's about 3/4" dia. , unthreaded, and opens into the left
port. Also, what are the two tubes coming out of each side of the SU manifold? Any good
reference material for making this swap easier? Thanks

8 Answers

four carb choices~

2 people found this helpful.

that EGR is on the exhaust manifold..mine cracked near there and ended up using some nickel welding rod to put it right~

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small motor...brilliant turning radius...I remember these~

1 people found this helpful.

A friend of mine made the same upgrade on a 70s MGB. If I remember to ask him about this over the next couple of days I will find out about the tubes and the rest for you.

1 people found this helpful.

Thanks.I'll look forward to what your friend has to say.

Did British Leyland and Rover use the same components....perhaps a Rover carb system might be stromberg or here we have carter....the Hitachi DCH-20 spend a weekend rebuilding on the kitchen table learning how these things are put together....but the "side draft" carb is a different critter with an oil pot and vacuum operated intake control~...wierdie~


The last remaining problem is the interference between the twin SU manifold and the original exhaust manifold left over from the Stromberg set-up. It looks like I'll be getting a header system to complete the swap. I have everything else I need......I think. Thanks

1 people found this helpful.

It is the last day of our civic holiday here in Canada. I'm working despite that. I managed to drop in on my friend with the MGB to see firsthand how his SU conversion looks. His car also came originally with one carb. So, this is what I surmise from looking at his car. The ports at one end or the othe of the manifold are vacuum ports. If you have no brake booster then plug them. The next thing is how the two carbs fit over the exhaust manifold. The B's engine was a two carb before emission laws. Not so sure about your car. The B's exhaust manifold was desgned for a two carb intake right from the beginning. The Stromberg manifold for the B was designed to work with it. So, what I think about your, (Spitfire was it?) car's exhaust manifold creating this interferrrence, is that it will never work with a dual carb manifold. Are you sure that you want a twin carb manifold on thst little motor? I have my doubts about that fitting without using a spacer to mount the manifold whether you're using a header or not. Let's see what you can come up with.

1 people found this helpful.

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