mix and match question

[austinsailor]

I've got a couple motors I want to mix some parts up on.

I have a 1951 Fargo, 228 ci, 4 1/4 stroke 3 3/8 Bore .010 over.

I have a 1948 desoto 236 ci motor only, 4 1/2 stroke 3 3/8 bore, .060 over,

Some of the pistons I'm selling for the machinist are 3 3/8, .030 over and .040 over.

Now the question. Can I take the rods and crank from the desoto, put them in the Fargo block and use the pistons that were for a desoto/dodge truck? The desoto block is bored out to far to go again, most likely. I think I can salvage the rest and have a good, even a bit bigger, motor in the Fargo.

Or, am I nuts?

[Merle Coggins]

I believe that would be possible. Bore the 228 out to match the pistons and use the crank and rods from the 236 and your 228 should become a bored out 236.

Merle

[austinsailor]

Well, I found out I was all wet. Both motors are 4 1/4 stroke, so there is no advantage to swapping. The difference is in the bore.

So, with the Desoto at .060 over, the block is of no use unless there are pistons bigger than .060 over. If it had been a 3 3/8 bore motor, it could be bored to take 3 7/16 pistons. I'm not aware of a size above 3 7/16.

Are there any pistons around that will work that are over .060 above 3 7/16? I know you can get custom ones made, but they're about $1000 a set. You can buy a lot of cores for that.

If there is nothing practical, I might just saw up the block and study what could be done to it. Things like the thickness where porting is done, how much a valve opening could be opened up, that sort of thing.

[Dave72dt]

Cylinders have been repaired with sleeves and rebored back to stock size and may be an option if you really want to save that block. Kind of spendy option but viable.

[Dave72dt]

Just reread your original question. Why not bore the Fargo until it cleans, probably at .030 or .040 and use those pistons you're selling for the machinist, sell your .060s. You end up with fresh, straight cylinders and a chance to rebore again if you tire that engine out again. A fresh rebuild is going to feel like a bunch more horsepower over a tired engine and I don't know how much you'd really gain with the extra cubic inches when you don't have that many to start with. A lot of the extra power feel is in the mind and not in the seat of the pants.

[austinsailor]

You are correct, that takes care of the Fargo. I'm wondering, thought, if the Desoto block has any use. Unless I can find pistons bigger than .060 over 3 7/16, it's nothing more than a boat anchor. Seems a waste, but that may just be the way it is.

[Young Ed]

I have seen .080 flathead pistons for some sizes.

[Dave72dt]

I did some research in my EGGE catalog which told me a stock 228 has a standard bore of 3.375 and a 236 has a standard bore of 3.4375. I think what you may have is a standard bore 236 fitted with .060 over pistons from a 228. You'll have to check it with a bore micrometer to be sure. .060 on a 236 should put the bore at 3.4975 while .060 over on a 228 will give you the same bore size as a standard 236. If that's what was done, you're good for boring the DeSoto to whatever you need to clean the bores up. Stick to the smallest overbore easily obtained to allow for future boring.