John Deere Power Block, 6"

Mike Davis · Mar 23, 2016

I pulled the block off my 1947 "A" john Deere and realized it has huge pistons, almost 6" wide. The block says "POWER BLOCK" 6". Does anyone know the original size of the cylinders and what is the max they can be bored. If I do have to bore it, where do you get pistons to fit? Any other info on this power block and pistons would be appreciated, thanks in advance.

ndbjda · Mar 23, 2016

Get a set of G standard bore aluminum pistons bore your power block .125 oversize. You will need to machine the tops of the pistons to clear the front of the power block. That will give you the opportunity to set the compression ratio where you want it. Would give you a nice running 397 cubic inch A.

buickanddeere · Mar 23, 2016

Lucky you with your finding the PB.
When the engine is apart. Now is the time to have that worn cam and followers ground to match the displacement and compression ratio of the PB and G pistons.
It's going to be nearly double the HP of a stock all fuel A.

Pete in MD · Mar 23, 2016

Here's some info.
Power Blocks

Mike Davis · Mar 24, 2016

Thanks a bunch for the info. I had no clue about the power block. I can now press on doing other work and ask my bride for more $$$, ha, ha. Thanks again to everyone.

John Deere Power Block, 6"

Mike Davis

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ndbjda

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buickanddeere

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Pete in MD

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Mike Davis

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