What do ya know about these heads}#458642 and #3978493? I looked on http://www.mortec.com and all I found out was that the first # is a 350 head and I think the second one is a 400 head. Are they worth cleaning up or should I just junk them? They came off of the 4bolt motors I got out of a boat a while back. The engine #'s were #3970014 it had the #3978493 head on it and a #3970010(this is the motor that I've got in the shop now making a 388ci, it is a high nickle block)with the #458642 heads on it. Thanks, Bobby

if the second set of heads is for a 400 I would be going back to that second "350" and making sure it wasn't a 400. It wouldn't surprise me if a boat came with a 400.

The engine casting number is 3970014, its a 350. They were both in the same boat. I got them for free, just had to take them and the gears(boat tranny) out. They were scraping the boat it was old and had sunk and stayed down for two weeks or so. I just happened to come by the ship yard on the right day and the owner said it would save him from having to pay his workers to remove them. It was a lot of work, took all day and had to cut the top of the boat off and use a small crain to get them out. The boat was about 50' long.

Good score. Some one must have replaced those heads on that particular motor.

Do you know anything about either of thoes heads? Are they worth cleaning up for later use or what?

not off the top of my head, buy I ASSume they are the big combustion chamber heads (76cc) So getting any compression out of them is going to be hard. If you have a set of 305 heads laying around compare the two, I bet those heads have combustion chambers that are twice the size, also look at the valve size as well. Unless they are a set of camel humps (casting marks on the end of the head) with 2.02, 1.6 valves they are probably not worth your time.