Several years ago, I bought a set of new pop-up pistons that were said to be .060 over for a 270GMC off of e-bay. Well apparently they are not as described so I want to sell them but need help in identifing the correct application. They mic out at 3.776-7 (this is at largest dia. of skirt) they are stamped .060 on top, pin size is .990. According to the specs that I found, this dia. is the same for a .060 over 248 as well as std. for a 270. However the 248 engine has a shorter stroke than a 270 so I compared the pin to crown height with a 302 piston (same stroke as 270) and they appear the same, so I assume the different strokes were taken care of in rod length. These pistons have an appox. 5/8" bump that covers about half of the dia. of the crown. Marked Zoller Heavy Duty, 493-BO. So my questions are "what is correct application, what cly. head is required, and any idea as to compression ratio"? Any help would be appreciated and can e-mail pics if needed. Thanks, Eddie
