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Discussion Starter #1
Not against using the existing Spica manifold as it is ported and matched to head. Open to all ideas. Thanks in advance for any info.
 

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Push hard and live
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Just curious, but “why”?

I’ve had bunches of three systems, Weber, Spica, and L-Jet. My favorite is Spica. Webers are fine, if done right, but to get equal performance, good behavior, and acceptable gas mileage requires more time and money with Webers than Spica.

If a Spica has been ransacked by a PO, it take a little while to sort it out, whereas Webers can be made to run fairly quickly. But, to achieve the three goals above, Spica is faster and cheaper.
 

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This is endlessly debatable. It comes down to our individual priorities, no? Yes Spica can and does work very well. I've spent countless hours over many years tuning it. Mine is set up well and causes no problems. I'm not new to it and have had this car for 25 years. But the car is slow, to me. Spica is not (easily) flexible to significant mechanical change.
 

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I would recommend using a factory Weber manifold instead of the adapters that join Weber carbs to a Spica manifold. See photo below showing the Weber conversion sold by Centerline that includes a factory manifold. My reasons for preferring this approach are:

- It is difficult to get a good seal between the carbs and adapters using the O rings and plastic pieces supplied with the kits for Spica manifolds.

- Can't mount a stock air cleaner & carburetor support strut to the Spica manifold conversion (at least, not without some modifications). That lack of a support strut may contribute to the air leakage issue mentioned above.

- The throttle linkage connecting the Spica bellcrank with the Weber butterfly lever always seemed klugey to me. I worry that the ball ends will pop off, since they aren't at 90 degrees to the direction of force. Admittedly, I haven't heard reports of this becoming an issue.

 

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Discussion Starter #5
Thanks Jay, much appreciated. Centerline doesn't offer the kit anymore but I think the individual pieces can all be had on the used market. Perhaps someone here has them around.
 

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Thanks Jay, much appreciated. Centerline doesn't offer the kit anymore but I think the individual pieces can all be had on the used market. Perhaps someone here has them around.
Yes. I just used the photo from the Centerline site because it shows all the parts you'll need in one picture. But sure, the BB or ebay are sources for manifolds, carbs and air cleaners. Centerline (and other Alfa parts suppliers) will have the Spica block-off plate, repro linkage bellcrank, repro support strut, rubber mounts, fuel pump and pressure regulator. Or, as you say, someone here may have these parts. I'd suggest starting a "Weber conversion parts wanted" thread in the "Parts for sale/wanted" section.
 

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As someone who has owned 3 105 cars that were converted from SPICA to Webers I agree with everything that Jay posted. The SPICA manifold can be made to work and I have seen them on race cars but for reliability the full Euro conversion is the way to go.
 

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Discussion Starter #9 (Edited)
I tried to place a 'wanted' ad in the 'parts for sale/wanted' but it was deleted for being a duplicate. Still looking for parts, so bump.
 

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Discussion Starter #11
Thanks, I've decided to follow other's advice and not use the Spica intake manifold which is the design intent of these kits.
 
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