The Stovebolt Site Forums The Shop Area Engine Shop '81 250 into a '51 3804

Who has done this swap? Can I use the mounts from the donor '81 1/2 tonner? Will the thermatic fan fit behind the AD radiator? I think I'll want electric fans anyway. Opinions? What else might confuse me?

Okay, next question then: What should the plug gap be on the '81 250 I6?

The shop manual says .035 plug gap for a 1981 250.
You could use the original 250 mounts, but they would need some cutting/welding/fab work on the frame side.
The radiator will have to move forward and down to accomodate the 250 fan.
I believe the fan on the 250 will be about 4 inches or so lower than your 216 fan. (measuring from the crank centerline)

Thank-you. The old plugs came out clean at .045-.050, and the new ones went in at .038. So I guess my timing will be a little reatrded from spec, but that's okay by me as I like to lug my engines: I imagine it gets me fuel economy. I'll let you know about that tomorrow, as I have a 250 mile trip to knock off through the coast mountains, and on the return leg I'll be loaded to around 1000 lbs.

So if I delete the belt-driven fan on installation and use electric fans, will there be clearance?

Tight behind. I have a pusher in front of the rad.

http://www.chuckthetruck.com/page26.html

Thanks, Chuck. Is your bellhousing in the same spot, or has the engine been positioned back a bit? I'd like to keep my stomp starter.

Your site, by the way, is nicely set up (not that I'm much of a judge), beautifully written... (that, I am in a position to judge: I, too, was educated at the end of a yardstick by penguins. Do you think it doesn't show?) ...but page 26, at least, is so rife with techspeak that it is barely comprehensible to a Doctor of Just Plain Truckin', such as my ownself. Even so, I enjoyed what I have read, and I will be getting to the rest. But right now it's 04:30 and I have a promise to keep.

Where the heck is your garage? I want to leave Epic #2 there for a bit...

I have no clue where the bellhousing was originally; the truck had a 230/3 speed/open driveline when I got it. I did bump out the front of the floor for bellhousing clearance, and I ran a stock-type fixed fan when I first put it on the road. The fan had about 3/4" clearance with the rad mounted inside the horse collar, instead of on the rear face as intended.

http://www.chuckthetruck.com/page16.html


Thanks for the compliments.