American Spec Engine - V12 E Type

[mph]

Does anyone know if there are fundamental differences between the US and UK V12 engines ?

There is conflicting information in various articles/books I've read so far, but the US model is generally presented as having inferior performance.

I know the US cars have a so-called "gulp" valve fitted which allows air to the exhaust side I believe. I think UK and US models have the same carburettors but are they jetted differently perhaps ?

I'm more interested to know if the US engines have different compression ratios, camshafts or other mechanical differences.

Help.

[tonys]

This would indicate that there was a change to US-spec compression ratio for 1974 (from 9:1 to 7.8:1)

http://nelsonsoares.hubpages.com/hub/Jaguar-E-Type...

I can't vouch for it's accuracy, though. I always thought the alternative ratio to the std. 9:1 was 8:1, but maybe that's what the 7.8:1 is!

The carbs listed have a slightly different number, ie CD and CD2 - don't know what the difference is.

The early 70s were still early days for emission regs., so were all US market engines the same, or did, for example, California, have different regs to other US states??

[Hooli]

tonys said:

The early 70s were still early days for emission regs., so were all US market engines the same, or did, for example, California, have different regs to other US states??

From reading up on specs for MGs years ago I'd say Cali had much stricter regs than the rest of the US back then.