Is there an easy way to identify what type of head is fitted to an engine?
I've got a set of low mileage 2002 heads that cost me less than the price of a pair of rockers, and I want to know how to check if they're S or R heads?
I know they're not E's as they don't have the "step".
R u talking tessi heads? if so they are both the same except the R head was sand cast and the S head cast in a different way due to mass production. That is with the 998S / 996R
With you mentioning E, I guess you're talking 748?? The R heads have 36mm/30mm valves and the pulleys are wider (thicker belts). The valve lift will also be about 1mm higher on both inlet/exhaust. After that, you need to pull the cams and check those.
If you do fit them, watch the pulley width and alignment. They are different. You'll need the wider pulleys for the lower twin set, and spacers etc to get the alignment correct. Saying that, you should be able to use your existing pulleys. Just bear in mind that whichever route you take, "something" will have to be changed.