one of the biggest gains to be made to 235s and 261s is by boring... and a bunch, .125" if the block is sound. In McGurk's dyno tests done on a 261 in the Jan. 1955 HRM article, An eight inch overbore really woke up the torque figures. There are procedures to stroke the crank upwards to 3/16 longer by offset grinding the rod journals to a 292 journal size and using those rods-special pistons will be needed and can be furnished by Ross?, or was it Egge? An eight over 235 is 252inch, and I have ridden in these-they have a definate whomp on your back when you hit them with 3.55 or lower gears, and with an additional 3/16 stroker its at, what do you know, 265! (definately the hard way-but you wind up with better rods) An eight over and 3/16 stroked 261 is a 292!! I think one of the card bearing Inliners has one in an early Chevy Twice racer. I would almost say to bore one .10" a real waste of time and money. All my experiances with hyd 235/261 were not good. those hyd lifters are huge and heavy, along with the solid rod type pushrods they make for a really heavy valve train--use solids and tube pushrods. find a reprinted McGurk hop up manual at panic's place? or amazon-Its the Bible for these motors. Maybe if ol' Frank used one of his stovebolt motors at the '38 or '39 Indy, instead of the Offy, He might have qualified!
A place to look for cracks, (have not seen mentioned on these pages) especially the 261s, is the main bearing webs, as it was common place for these ol' warriors to be "lugged" around intersections due to their low speed torque, (this was a "tip" offered in Hasting piston ring packages) back in the day as they say. See, it dont hurt to be old, Imagine spending a fortune on boring and pistons only to find a crack in one of you main webs- these motor only have four mains (but they are big).
Last edited by preacher-no choir; 09/20/11 05:22 PM. Reason: main webs
