I personally would just be looking for another engine.
I am surprised they suggested doing valve guides, I thought that was a bit of a lost art these days.
That pricing seems way off to me, doing a set of guides, then re cutting seats and lapping new valves in is at least an hours work, strip clean and hone is another, so I wouldnt be trusting that, but then they have quoted you $140 for a gasket set available on ebay for $26.. seems fishy..
No the gasket set wont have carby gaskets, so to rebuild that will be extra again. I would be very surprised if they were under $500 for the whole job.
