Cross breeding an 87 312-8 and a 74 B-80, thoughts?

[Raz900 0]

So as the topic says... I have a B80 that my dad bought new in 75 ( a 74 model). It served well over the years getting a new mower deck and a new K181 in about 90. Last week, the trans I'd put in a couple years ago (8 spd from a C100) failed tearing up both NLA 1533 bearings. So I found a 312-8 I just brought home tonight. From the Magnum SN (1625403623) and horizontal muffler seen in other posts, determined it's a 87.

The steering and some of the electrical on the 312 is toast. The dash/steering support is broken and the bushings are almost totally gone,1 headlight is shot, none of the tires hold air and the brake pedal has something up. Leaks gas somewhere too. BUT, the 12hp runs well, pumps 125psi on a compression test, the frame is VERY clean and the trans,PTO, pulleys etc all works well.

Anyone put the sheet metal from a B or C on a 312 type frame? I'm gonna try it, but figured I'd ask before starting the adventure. Not looking for restoration level fit as the B80 metal is rusted and needs painted. But to use the steering, hood and other parts that work, I'm just going to move everything over. All 4 wheels and chains, tie rods, gas tank etc. I'll use the 312 wiring as much as possible. Plus it'll still be 'dad's tractor' if it looks like the 80. Not worried in the slightest about missing holes or braces, I can cut and fabricate just about anything. Assuming it might be off by 2" or so as the B was a odd frame length, no?

And yes, I'll post pics as I go.

Steve

[TT-(Moderator) 1,162]

:WRS:

They're close enough that it shouldn't be a major project.

A C series hood will take care of that extra two inches of frame you're gaining. :handgestures-thumbup:

[jay in nc 210]

you are almost a new c120 owner congrats.

[JimmyJam 542]

:text-welcomewave: Sounds like a cool modified! Giving Dad's tractor a new life!

[ericj 1,579]

why not swap rear over into the b80, not sure if the 12 hp will fit in to the short frame thought. with the trans swap you could be back up and running in a couple of hrs. then find another wheel horse with a bad motor to put the 12 hp on

eric j

[can whlvr 994]

i like ericj,s idea also,might be feasable,but maybe the shifters might have to altered,dont know for sure as ive not worked on a short frame

[Raz900 0]

Thanks for the replies. I'm still debating the best course of action. I was really looking for a C100-C160, but this came up first an hour from home. With snow in the area, I was kinda pressed for time to get something to plow. My driveways too long to shovel, daily driver is a Lincoln Mark VIII (rwd) and truck's in the shop. For $250 the 312 fit the bill close enough.

I did a once over on the 312. Oil change, took deck off (rust holes under belt drive as expected), swapped the 22x9 rear tires for my 23x8.5 with chains, fit the plow (really don't like not having height adjustment on the lever.... had to adjust the 'skis' I'd put on the blade to keep it from digging in), drained the mud water from the axle filled with mix of 30w and 80/90w for now and checked everything else over.

The rear seat pan has definitely been repainted, looks to have been sanded with 80 grit on a grinder from the swirl marks. From the dents on the hood, a welded piece that sorta holds the left headlight in and missing bolt here and there, I'm almost thinking it was rolled over on it's left side and completely repainted at some point.

The fuel bowl wasn't tight. drained it, cleaned carb out and put it back together. Gas cap is busted, thus it vents straight to the air all the time (new one on order).

The brake had a spacer on it and tighered till the nut stopped. I guess the PO though it was supposed to get tight? This had the brake pedal leaned back toward the seat. Took spacer out and set it correctly now it's inline with the clutch pedal as it should.

Half of the safety switches are disabled, which is fine with me, that was the balled up wires for the most part. The engine also has a oil sensor in the pan and there's an empty light spot in the dash that says 'engine oil'. Not sure if that was original for a 87?

So for the winter, the 312 look will be the plow. After I finish repairing my 99 F150 (new bed, sandblasted frame, cab mounts, etc) I'll start painting the B parts. Hopefully the steering in the 312 holds.

Oh... and swapping the rear into the 80. Back in 84 or so, dad painted it Cadillac 'Autumn Maple Firemist' when he did his 1970 Chevy Blazer 2 tone with that color (purple/red) and Black Cherry. So it's a combination of rust and purple. The 312 frame, probably a repaint, is rust free and red. Saving myself from disassembling the 80 frame to repaint it. The tins are a piece of cake in comparision, light sandblast, sand with 150, 1 coat epoxy primer, 2 coats high build primer, sand with 320, sealer coat of epoxy primer and shoot the Valspar tractor IH Red I already have from doing the new deck. Needing something to plow during the winter, I can do the paint work to the tins then only have it down for a day or 3 to swap the new painted parts over.

[JimmyJam 542]

Sounds like you are certainly on your way! You have been very busy, all before the snow flies! Would like to see pics!