Hi,
VW heads are not know to have good flow in stock version . Old vw head have really small valve .
When you increase cc, you increase exhaust gaz volume ( and specialy if you increase flow admission with heads job or Okrasa heads with dual carb). Because exhaust is restrictive, you increase back pressure and temp. 8000 km is not a pb, but be sur that the life the head will be shorter, specially exhaust guide and seat . At 2000 rpm with JD engine config, you have volume gaz near same than full rpm in sotck config .
So don't use stock exhaust .
Hope you understand my poor english :roll:
Eric Simon
udog wrote: