Next Step on John Deere A

Two years ago, we bought a 1951 John Deere A from a gentleman that had bought it a year before from someone in the midwest. He had been having very limited luck with it at local pulls and wanted rid of it. We were told it had a powerblock and an electronic ignition but not many other details. Over the past two summers, my dad and I have achieved some success by changing the small little details like tire pressure, hitches, weight ditribution, fuel mixtures and air intake to name a few . We manage to place in the top five around the local pulls, but like most, we just feel as though we need that little extra. This is what I know about the tractor: has a #3 powerblock (not sure if it is bored), the head is not the stock head because the frame rails are notched to accomodate the added width. The carb is a DLTX 81. I know these were on the 60's. Has an electronic ignition. Like I said we know very little about the internal workings of this tractor. We are hoping to have it tore down by mid november to get the bore and stroke measurements, because I am sure that plays a big role on what we can and should do. I am thinking the next step would be to bore the power block and lengthen the stroke out but not sure how much of each to make it competetive yet reliable. Is that even a posibility? This tractor serves one purpose and that is tractor pulls on the weekends.

You say the frame rails are nothed what type of intake/exhaust maniflod does it have if its 2 piece with 2 intake runners it has a 60 head on it make shure where you pull (or plane to) they allow the 2 barrel carb. on lettered series tractors.As far as future mods. 6.125 is easy on the bore sroke 9" or 9.250 w/3" journals

Must be the situation here. Why put the 60 head on it? Will I be able to use this head with a bored powerblock and 9" stroke?

I don't know for sure, but the 60 head may flow better. You need the 60 head for the 60 manifold to run the 2 bbl carb. When you bore and stroke, tell the shop building the pistons what you are doing and what head you have, what fuel you plan to run etc and he will build pistons to work with what you have. You can not buy a mass produced piston that is just gonna work with a stroke and a 60 head.

The 60 head lets you run the duplex manifold/carb.

I normally bore the A/60 PB's to 6.125", either welded rods or billet (Billet cost more, look really pretty, and are more accurate). Contrary to popular belief, they aren't any easier to install than clearanced welded rods.

As "north puller" stated, whoever does your work needs the stroke, dims on the PB, CC's of the head, etc, to set the pistons up right.

Something like either of these work nicely.