can anyone explain to me the technical advantages of boring your engine, and what i should do. im rebuilding a racing 225 and i dont know a lot. this is going to be a learning experience for me. its always sounded fun and i already have some big compenents, like 4bbl intake and headers. the carb, crank, and cam shouldnt be to hard to get but i dont know what to do to the pistons or the head.

I am going to assume you mean boring the cylinder. Basically the machine shop "redrills" the cylinder, to increase its diamater. This can be to simply increase displacement, correct problems like cylinder taper or deep scratch marks, or resize the cylinder to fit an unconventional piston/rod combination. Boring just to increase displacement is "boring", pun intended. Thats what the blue oval guys do cause they're not smart enough to think of anything else. Now, if you meant align boring, that is to make sure the main cap and bearing surfaces are perfectly aligned, so your crank doesn't have any flex at all when spinning at 5500+ rpm.

_________________
'67 Dart 270 4door, 225

Another advantage to boring the cylinders oversize (besides adding displacement) is that the bigger cylinder helps un-shroud the valves, this helps the engine breathe. You need to increase the valve size to really take advantage of this.
DD

what are the typical sizes for oversized pistons and valves, and if i got them bored what hardware would I need to install the new size pistons and valves.

the most common i think ate .010, .030, .060 for over bore, not sure on the others though

Justin

If you use the KB268, the 1 mm oversize is 0.085 and the 1.5 mm is .105 oversize. These pistons can be used either by using the 198 rod on a 225 crank or by increasing the stroke to 4.5". Doc has an outstanding article on these combos.

_________________
Gilly

1960 Dodge Pioneer
"Long Rod" /6, A833 Pistol grip Hurst
8 3/4" w/Suregrip and 3:91's
Still have more parts in boxes than on the car....