I wouldn't worry too much about the size difference - you'll become accustomed to it as quickly as you have with the Precision. You will have to adjust to changes in maneouverability and momentum that come with a heavier, less nimble boat. Tartans of that era have a good reputation... it goes without saying that you need to get it properly surveyed.
The Atomic 4 can be an easy engine to live with, quiet, plenty of power, smooth running as long as it's in good condition. The major downside of an A4, assuming it runs reliably, is its effect on a possible resale at some future date. Diesels are preferred despite not necessarily being the best application of the type.
The other issue to sort out before you make the move is a place to keep it... moorage is either hard to find or expensive, or both, in most regions these days.
Best of luck in your plans and decisions!
".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)
1984 Fast/Nicholson 345 "FastForward"
Last edited by Faster; 08-22-2008 at 09:57 PM.