Are early '78-79 US intakes the same as Euro intakes?

[Gunter]

For 911's: On an early '78-'79 US intake, the airbox, FD, bigger intake runners, etc. are different from the later versions with Lambda.
Are the Euro intake systems the same as the early US system?
Example: Would a '81 Euro have the same intake system as an early '78-'79 US?
Thank you.

[Oh Haha]

Geez, that was fast!

[Gunter]

Anyone?

[SpeedracerIndy]

If there is anyway I can tell from looking on the outside of my engine I would be happy to help.

[Gunter]

Thanks. Yes, you can help. Measure the outside dia. of your intake runners; if they are 47.5 mm, the are the same as the early US intake runners.
But I am not sure if ROW are the same as Euros.

[dd74]

I think the '80-'83 intakes are the same size for both ROW and U.S. CIS systems. The '78-'79 intakes were largest whether ROW or U.S.

ROW should be the same as Euros. The main difference with CIS 3-liter engines between the U.S. and ROW engines lies in the higher compression of the Euro motors. In 1980, compression for the Euro motor was bumped up to 8.6:1, then in '81-'83, it was bumped up again to 9.8:1. Factory timing for the Euro motors might have also been advanced over the U.S. versions, giving them the higher horsepower they enjoy.

[SpeedracerIndy]

I'll see what I can come up with when I get home from work. What about a part number or casting number on the intake runners. I seem to remember someone asking for that a while ago when trying to find the same information.

[Gunter]

Thanks dd74 and SpeedracerIndy.
Easiest way is to measure them; the early US intakes are noticably larger (~47.5mm), the later '80-'83 US with the Lambda system had smaller intake runners by about 5mm.