340 crank into 360 block bearing spacers

Anyone make bearing spacers to put a 340 crank into a 360 block?

Thanks

What will you do about the rear seal situation?

I want to say Mancini used to sell something like that. But like Mr. Porter I also wonder about the rear seal situation.

Why would you want to do that?

if bearing spacers were to be used, wouldn't the 360 pan still be used with the 360 rear main cap ? or am i missing something ?

Thats the way I thought it would be.. but as far as I know you would just use 360 seals

I think the rear main seal is what is in question.

I would have thought that a stock 360 seal would still fit the block

I don’t believe the seal surface diameter is the same between a 318/340 crank and a 360 crank(I believe the 360 is larger)....... but a quick measurement would clear that up.

The 360 seal is larger and it fits into the block(2 pieces, top and bottom) and the bearings fit the
block

The seal has to fit the block.......and the crank.

If the seal surface for a 340 crank is .200-.300 smaller than a 360 crank..... the 360 seal won’t even be touching the 340 crank.

Thats why I think the old rope seal would work(if you can still find the rope seal)

I’ve never really looked into it before....... but it appears as though the 340 seal surface might actually be a larger than the 360 seal surface.

If that’s the case, then the seal surface on the 340 crank could just be turned down to the 360 size.

I never looked into it either but yes the crank area could be cut down to fit(I believe).. all my
engines have been 340s and I never looked into the 360s(except one B and one RB engines)

The rear main cap outer diameter is way different, smaller, on the 360 motors compared to all the other SB Mopars, so the oil pan rear seals are not interchangeable along with the oil pans also

The reason I milled my 340 cap so a Magnum rear sump pan will fit

Indeed. You lose over a quarter inch of stroke with a smaller bore. A stock 360 crank will take a surprising amount of abuse. The high RPM oiling is the catch. Keep it below maybe 6800 if you don't want to redo the oil system. I put a 360 crank in a 340 and it turned into a rod bearing eating PIA.