There is no point in trying to fit the Mk2 layout into a Mk1. Both engines are vitually identical apart from slight changes to valve timing, and the use of slightly superior injectors on the Mk2.
Take it from me you wouldn't notice any difference between a 1.8 Mk2 engine in a Mk1, and the standard 1.8 in a mark one. The Mk2 has a few extra attachments on the fuel injection such as An extra air valve to stop the tickover falling below 750RPM this is located on the driver side strut mount. There is also a diaphragm fitted to the metering head which is supposed to increase throttle response, but most don't work, and even when they do, you are hard pressed to notice!
The main reason why VW put the metering head on the left hand side on the Mk2 was for safety.
In the event of a frontal clout. On Mk1's the fuel, (under high pressure). is damn close to the battery, as the metering head, and fuel filter are directly behind. it doesn't take a genius to figure out that in the event of a frontal smash, any sparks from the battery could quite easily ignite any fuel released by the crumpling metering head.
I'm sorry if i have gone into too much depth here!
But i hope that answers your question!
