I wouldn't spend a dime to rebuild a 305. If it's running good, run it until it drops, then swap in a 350. You can get a good 350 long block for $150 at your local Pull-A-Part. Just the other day I posted about a 4-bolt main roller cam block available for $145 that I spotted in the local yard. If you buy a 350 now, you can rebuild it at your leisure and take the time to find bargains on your parts.
