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Spitfire New Spitfire Carb

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tomkatb

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My son and I recently had our Spitfire 1500 engine rebuilt in or 77.

It was decked, high compression pistons, fully balanced, new 74 exhaust, 3 axis valve job, new stock cam, and aluminum flywheel.

It runs well, but currently has the Stock Stromberg carb.

I was wondering if anyone has tried the SU hif44 1.75 carb set up on this car which is used on the MGB.

I think the engine is being starved for air. How does one tell if that is the case?

Larry
 
That is another option. The 1.75 carb will flow about the same as two 1.25's. But, less hassle in every way. Mini guys use them I think.

Wondering if anyone has explored this?
 
Yes John Kipping says a HS6 will work very well. Problem is you need to get an intake from some obscure model because it has bigger intake runners. I guess you could ream out a stock intake OK. A racer in Greenville, SC i know has some stock intakes he opened up that he says he will sell me. He used them in racing, but they are now outlawed and he can't use them. He was also supposed to sell me a rebuilt differential, but I can't get him to pony it up.
 
I would be interested in how to modify one or perhaps buying one already reworked. I have a spare manifold I could have machined.
 
I realy don't know how he did it. Most of the intake could be ground from the outside. But I suspect he had to cut open one end of the manifold latera part, grind it and then welded it back. Remember this is a racers trick and they can do almost anything. Next time I'm in Greenville (and that should be soon), I'll stop by and ask him.
 
I stopped by Precision Automotive in Greenville, SC today and talked with Larry Tippett (864-232-5460). He is the guy that has the modified single carb Spitfire intakes. He has three he will sell as he can't use them any more. The part of the intake that connects to all four runners was cut open, reamed out and rewelded. The entire intake was ported and polished and has been opened up to take an HS6 carb. He also beveled the mounting flange to tilt it upward some. He says this intake makes a big difference on a 1500 engine ove the stock set up. He wants $100 each for the intakes. I thought that was little high until you consider paying a machine shop to do it. I will likely get one when he does my differential. Please note it no longer has the smog connections of the water connections for the colling system.
 
Bill - is the net-net that he has the manifold/intake to a point where they are close to bolt-on for a HS6 carb conversion?

Sounds like that is the case, but I wanted to double check. Is so, I'd love to take one off his hands.
 
tdskip
Not sure I understand your question. But, the mounting flange for the carb has four threaded holes. The intake was done to mount a Stromberg, but he had an SU carb sitting there. We fit it up to the intake and it seemed to be a fit. I'm sure lots of folks here can weigh in as to whether the Stromberg and SU have the same bolt. THe SU carg (HS6) was a two bolt flange on the diagonal. He also has some carbs he would sell but said they would not be good on the street as they have been heavily modified for racing.

All I ask is that you not buy all of the intakes.
 
Bill - this is your find and there is no way I'm going to snake you (or anyone else) on them.

I'm just interested and trying to learn as I go here.
 
Don't worry. I had my chance when I was there. Just couldn't pull a Benjamin out and give it to him without pondering this a little. I will get one when I get him to do my diff, if he still has one. If I was too worried I wouldn't have posted the contact info. But thanks!
 
[ QUOTE ]
Yes John Kipping says a HS6 will work very well. Problem is you need to get an intake from some obscure model because it has bigger intake runners.

[/ QUOTE ]

You can find large runner 1300/1500 manifolds regularly on e-bay and at swap meets. They were stock on one or two years production.

The real restriction, and it's minor, is that the cross runner isn't quite 1.75", so you've got to neck down from top to bottom.

You'll also find the carburetor doesn't quite sit square to the runner when fitted up. Hold any ZS manifold and a 1.75 SU together, and you'll see what I mean.

John did use a specific manifold from a 1500 odd-ball application that wasn't available in the US. It made it easier, but it's far from difficult to do with the bits and pieces here in the US.

As I recall, he found performance to be comparable to dual 1.5 SU's, up to about 5,000, then the larger thoats of the duals surpassed it.
 
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