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**Burque73** · 03-04-2020, 11:28 AM

If they are the same head, I would suspect the cams to be different. The 1100 cam lobes may hold the valves open longer or wider to let a larger volume of air/ gasses pass through.

This is coming from a carpenter, not a mechanic, so it'll be interesting to hear what others say.

**Burque73** · 03-06-2020, 12:06 PM

In comparing the part numbers on Alpha Sports website, I noticed the head is in fact different, but to my surprise the cams were used in a few different engines.

11100-49830

11100-49020

intake cam 12711-49001

Exhaust cam 12721-49001

I don't understand how this works. I thought maybe since the cams were the same, the valves would be a different diameter, but that's not the case either. Although, this did exclude the 850's.

Intake valve 12911-49020

Exhaust valve 12912-49020

**duaneage** · 08-31-2020, 10:45 PM

Combustion chambers are smaller on a 1000. Using the 1000 head on an 1100 will yield nearly a full point increase in compression. Conversely a 1100 head will lower the squeeze on a 1000.
The 1100 jugs with a 1000 head is a good candidate for performance cams if you can afford them. You'll make the most of longer duration valve openings.

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gs1000g and gs1100g

gs1000g and gs1100g

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