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The difference in the BBChevy journal which is 2.200 and the FE Ford journal which is 2.438 is .238 so with the 391 truck crank having a stroke of 3.784 you can stroke it .238 thousands with a perfect crank. We will stroke most of them to 4.000. You could possible get 4.020 stroke with everything just right. We do these for some race applications where you can not run more stroke than this or if a customer wants a steel crank but does not want to spend 2400.00. You have to remember they are about 35 years old and were used in heavy trucks so they had a pretty rough life. I have made up to 800HP with these cranks but have also had some cracked when we freshened the engine and wet magged the crankshaft which we do on all of our engines. You will spend at least 800.00 easy doing one of these cranks right if you have the core. You have to turn down the nose and re key it, machine the back of the crank for a spacer to bring back to the right size for converter or regular transmission pilot bearing. Of set grind the crankshaft and either widen the rod throw by side grinding into the counter weights which is quite expensive or narrow the rods and leave the crankshaft the stock width and narrow the rods and rod bearings. This is not the ideal project for the regular guy trying to save money. The Scat cast steel cranks arwe good for up to about 750HP. I have had some out there for about 2 years that are making between 700 and 7550 with them and no problems. I do use a lot of billet crankshafts for some of the higher end engines that will make a lot of power or for customers that just want a billet. Make sure the other parts that you have will handle 700HP before you worry to much about the crankshaft. Hope this helps and good luck, Keith
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Keith C
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