Depends how competent you are.

If i were you and you have all the parts, id build it my self and just use a local engineer to do any machineing work you require.

Buy far the best route, this way you can really appreciate the engine knowing that it you who built it. (prob also more likley to treat it kindly when on the road )

If you cant do it your self, what id do is infact ask my local engineer to do the whole job.

If you have all the parts, id say its 3 days work to strip, check/machine parts and rebuild.

Take a look at my resto thread, ive done a step buy step guide to an overhaul

Rs1600i
https://passionford.com/forum/restor...storation.html

Aston Martin (but principles the same)
https://passionford.com/forum/restor...and-video.html