Here's the deal: I'm pulling my tired old 305 and dropping in a 350. The 350 only has about 10,000 km since overhaul, but has been sitting in a truck in a field for the past 10 years. It has been started two to four times a year and runs fine... now is there any need to rebuild it, other than the potential for leaky gaskets? Or is that something I can put off say, until this winter, when the car will be garaged?

 

Best bet is to pull it all apart and replace the "soft" material (i.e. gaskets and such). Get it out of the truck and on a stand and go at it. Also pull the main caps and check the bearings for uneven wear. Even tho is has been started up soft gaskets can go bad, and it is better to be safe than sorry.

Plus opening it up will save you TONS of trouble if there is something wrong inside it. A guy off here, xpndbl3, bought what he was "told" to be a high performance engine, only to open it up and find all the bearing washed out and tons of damage done to the engine. And he was about to slap it in his car, so you see what I mean by open it up to check it.

Plus a complete gasket kit costs about $25-30, so for that little in insurance knowing there is nothing wrong, I think is worth the cost.

PS Just make sure you torque everything back down, don't want to litterally "walk" your crank

Good Luck!!