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Hi Guys,

I've got a 68 with a 396 325 HP BB. Is it possilbe to modify this into a 427? I assume the differance between the 427 is bore or stroke?

Another thing. Why would the BB 396 Engine rebuild kit be nearly twice the price of the BB 427 Kit? I'm going from the Classic industries catalog.

Thanks, Mark J
 

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You would have to bore a 396 .154 thousanths from 4.094 to 4.250 and that would leave extremely thin cylinder walls. Rebuild kits should be just about the same price. They use the same bearings and gaskets, pistons and rings are all that are different.
 

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An old hotrodders trick is to stick a wooden pencil between the cylinders through the side freeze plugs and if it won't slide through, sonic check her b/c it probably will bore out to .155" over to create the 4.250" bore of the 427.

pdq67

PS., if the pencil slides through, I would look for another block w/o sonic testing it.
 

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As far as I understand it, the 396 and 427 share the same (or similar) crankshaft but a different block - the 454 is block is the same dimensions as the 427, but different from the 396. The 454 crank would have a longer stroke. I could be mistaken, though, someone please correct me if I'm wrong.
 

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What demensions are you looking at that are different on the 396 block than a 427 or 454 besides internal?
A 454 4.000 in stroke crank with a .030 bore 396 block makes a 427.4ci motor.
Not looking at their catalog but everyone has their reasons when they price their kits. They may have a hard time getting 427 pistons or parts Im not sure. Also It could be that his supplier is charging him more. And last make sure its the same quality parts in each kit. The 427 kit may be listed with a steel crank and the 396 has a cast crank for example.
 

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why not just bore the 396 ( actually 402) out .30 for a 409 or 60 over for what ,, about a 417?
 

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OR for about the same money, start with a 454 P/U core block and bore it out to say a.060" over, then use your rotating assembly to make about a 440" motor!

Or boring it an 1/8th over will make it right at a 452" motor!!

But for all this trouble, I would save the 396 IF it is stock and make a 496" motor!! Then you can make BIG easy power!!

pdq67
 
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