Mk1 Clipper 1.8 Head conversion advice

Hi guys,
I am after some advice on my clipper head. I am wanting to know if a 8v gti head will be a straight swap cam shaft and all.
And also would I be able to use the exhaust manifold. If so is there any difference between the single and double outlet to the down pipe as I am looking at both.
I have done a tonne of work on my first Clipper this year and now feel its time to make her sound a little better as the exhaust need replacing anyway. I am not doing this for performance.
Thanks guys any advice will be very grateful Drew.
 

yes, but what carb are you planning to use?

go for the double branch type downpipe if possible, just make sure its a kinked one to avoid your roll bar