mk3 golf gti 1.8 8 valve into mk1..please help

i have had the offer of a mk3 gti and am having a lot of running issues with my mk1 atm was thinking about taking up the offer and putting the engine into my mk1! is this a common conversion or not worth the hastle?? cheeers jake

Maybe the running issues are something other than the engine? What kind of running issues? What model mk1, etc etc

Also, there's a good guide on the left - worth a read and follow the links etc.

Well its a !.0 mk1 and has already had an engine conversion to a !.3. it has had a 4 branch manifold, full exhaust, 28mm delloroto carb, new filters plugs leads and induction kit. it has always been a slow car for a 1.3 with these modifications and it runs really boggy. it has always breathed oil pretty heavily aswell. i have now had the issue of coolant/ oil levels pretty good but the car is still overheating and smoking a rather lot :/ any ideas please??

What was the HC reading on the last MoT?

MK3 GTI is 2.0l not 1.8l
use the bottom end with mk1 GTI 1.8 head and ancillaries, but is a lot of work to make 1.1 or 1.3 a GTI