Maximum Bore + Stroke

4" bore with a 1/4" longer stroke + 225 inches, with a 4 3/8" stroke it = 239 inches. The difference in torque is amazing!
 
Crazydaddyo said:
Yes, I have broken two cranks. They both were B cranks ground to A mains and rods. Rod journal offset ground .187" for a total stroke of 3/8". Fillet radii were too small, but even .125" - .187" radii are hard to get with this big of an offset grind. Bore was 4".

As Bill has said, If you are only expecting your engine to go short distances fast, stroking it is advantages. But if your building a touring engine, then changing the stroke is a waste of money.

Head, Cam, And carb are your best "bang" for the buck.

I prefer the T-5 trans. but I will be banned from this sight if I talk any more about "non-stock" alterations. :rolleyes:

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I would tend to disagree with that. If I were to build a "touring" engine I would probably go with the 1/8' off set grind. I think the added torque would make a more tractable engine or power band. Too many try for the higher RPM's and end up shaking something loose. Of course not all but most of the amateur, "shade tree", builders have problems when they wind them up too high for too long. My self included.
 
Yes, I think a bigger stroke would help the low RPM power, just where you can use it on the road. No need to rev it up and strain anything. I guess this is pretty much what Bill already said.
 
just plain bill said:
I would tend to disagree with that. If I were to build a "touring" engine I would probably go with the 1/8' off set grind. I think the added torque would make a more tractable engine or power band. Too many try for the higher RPM's and end up shaking something loose. Of course not all but most of the amateur, "shade tree", builders have problems when they wind them up too high for too long. My self included.
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I was referring to the 3/8" stroke in my statment. Sorry I should have made that clearer.

You are right the increased stroke will give you better torque. And as long as you don't go much more then 3/16" you will still have a motor that will hold up to the rigors of touring. In my mind the cost of stroking an engine ($1,500 - $2,000) is a little much to add to your touring engine build cost

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If your going to spend that kind of money, a swap to a pinto or chev II with a 5 speed is what i woud do (or a flathead). I know , it won't be 'original" then.
Paul in CT
 
Don't want to open up that can of worms. My choice is to keep the original engine. I like the honest simplicity of the Model A. Just looking at some concealable "tweaks". :)
 
I agree with Vince and George that you already have plenty of stroke, and adding to it won't increase the cubic inches by much, even if it does give you some more torque AT LOWER RPM's.

I'd use a H/C head and counterweighted crank, and if you want more speed use a 3.54 or 3.27 rear end.
 
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