I recently bought an incredibly pristine 1985 series 3 XJ6 with an engine problem. I got the cylinder head off and there is quite a bit more damage than I had hoped so the engine will have to come out, at a minimum it will need a head and one piston. I can pick up a complete 1991 XJ40 for $300. Is the AJ6 and 4 speed tranny worth the effort to swap out? I have been a mechanic since 1979 so the actual swap and wiring isn't an issue nor is the rebuild of the original 4.2 . In the end both options will be comparable money and the swap will be quite a bit more work. Part of me would prefer to keep it original but the lighter 24 valve 4.0 and overdrive tranny may be worth the extra work, at least it would still be all Jaguar.

 

The AJ6 swap has been done before with good results. Good info if you search the archives. There's a long running thread on the process.

Cheers
DD

 

This should help

https://www.jaguarforums.com/forum/x...es-2-a-101137/


Cheers
DD

 

Here it is Doug. (Wilfed88's build)

https://www.jaguarforums.com/forum/x...engine-107712/

 

Thanks for the replies and information. I went ahead and bought a low mileage 1991 XJ40. Looking forward to getting the Series 3 back on the road.