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Rob 930 Rob 930 is offline
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Join Date: Dec 2002
Location: Seattle
Posts: 568
I had Bill at Xtreme do my head work - on original 930 heads. He massaged them to a very large degree. If you're going to open up the ports a long ways, install larger valves, twin plug, fire ring, properly plug the air injection ports, and go the whole mile matching to Carrera manifolds for EFI, he said there's no performance or cost benefit to using SC or 3.2 heads. So I went with 930 heads for the higher heat resistance. If you're looking to bolt on relatively stock heads with modestly larger ports, then the others may do. But Bill had other reasons for preferring to start with 930 heads, the details of which I can't recall anymore. It had something to do with the radius inside the ports that made the 930 heads more suitable for porting. From what I learned, I'd say this: if you own 930 heads that are rebuildable, and you're planning significant head work, then why not use them? Otherwise you're spending money on expensive cores that you'll still have to work on. If you have some usable SC or 3.2 heads around and want to use them essentially as is, then they may work for your application. But unless you plan to use the SC or 3.2 heads as is, you might as well start with the 930 heads if you have them. You get the benefit of the RR350 alloy with 930 heads, plus, why pay for expensive cores that you don't own?

By the way, there's no problem with sealing Carrera manifolds to 930 heads that have been ported properly. And these intake ports were opened (as was the manifold) to about 42 mm. The first photo shows that there was plenty of meat left. I've had no sealing issues whatsoever. The other shot just shows some exhaust porting.





Old 10-13-2008, 03:12 PM
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