The 261, with its thicker cylinder walls and different water jacket will handle a considerable amount of overbore. It's probably possible to get close to 300 cubic inches with a combination of a radical overbore and the stroker crankshaft that's described in the tech article. Since the 292 rods only partially solve the deck height problem created by stroking, it's going to be necessary to have a set of custom-built pistons made, so why not just include a 1/8" overbore while we're at it? Just ran the numbers- - - - - - -a 3 7/8" bore with a 4 1/8" stroke gives us a 292 cubic inch displacement with an original-looking engine. How's that for building a real sleeper? That's one that might actually benefit from the added carburetion lots of folks like to hang on a stovebolt.
Jerry
Edit: After a bit more research- - - - - -the 292 piston can be made to fit this setup with just a bit of machining! If the 261 block is bored to accept the 292 piston, it will stick out the top of the block .073" when assembled onto the stroked crankshaft with a standard-length 292 rod. There are two 292 pistons listed by Sealed Power that might work, a low-compression hypereutectic cast piston with a .312" recess in the crown, and a LP gas engine piston with a .150" recess. Either one could be machined down .073" to give a zero deck clearance without compromizing the strength of the piston crown. The LPG piston has no offset on the wrist pin, which would result in a somewhat noisy engine due to piston slap, but it would have higher compression with the smaller dish in the crown. (good for racing, IMHO) The lower-compression piston with the .312" dish would be better for street use, since it has a .060" offset, close to original equipment specifications for the 261 piston.
It looks like we can build a stovebolt-looking 292 engine with stock parts! How cool is that?
Jerry
Last edited by Hotrod Lincoln; 12/12/2008 6:25 PM.
