Do not do it.......porsche people will not like you, and most have never ridden in one.
If you are bold ....(ignorant) and still want to create one. email me and I will tell you all the issues that you will run into.
the costs of doing it right are about
10k=car 74-77(76-77 is better)
5 k =engine
3k= kit
2K =other
here is where the tricky part is.... if you go above 400hp/400tq you will have cooling problems (below the kit radiator will be fine).
also if you go big power you will lunch a 915 box. they are pretty much useless because you will be shifting too fast (and it will not shift fast anyway)
you will need to go to a 930 box shorten it , modify the mount (i have a jig for this), rework the axles, change the t bars front and rear.....etc.
there is way too many things to deal with that you will need to know.
Yes I have more money in the car than if I would have bought a nice SC and upgraded to a 3.2
Keep in mind that I only bought my car (in decent shape) for 7K
email me if you want but keep in mind to do it right they are not as cheap to build as the conversion companies would like you to believe.