i got a dumb question

[mrbeerbaitnammo]

what would the exact bore size be to bore a 4.0L 242 HO .30 over, and what is the max and the measurement you can over bore on that engine, and by how much does that change the displacement and horse power?

[OhioYJ]

.040" is the most you can go, I think I'd stick to .030" though. Going .030 over on a 4.0 liter motor will give you roughly 3 cubic inches, your 242 will now be a 245. Anyways, in many case the power isn't made from the extra cubic inches, its unshrouding the valves that really helps.

Don't expect your Jeep to be a hotrod just from boring it over 0.030, its only 3 cubic inches, which may equate to 3 hp, maybe 10 from giving the valves some extra room.

[mrbeerbaitnammo]

valves are unshrouded, i did the port and polish, opened up area around the valves real good, but here is my predicament, i am stationed in germany, there is a machine shop here that will bore my cylinders, but i need to know what the bore size i want is so that i can convert it to metric, so if you could or anyone could, give me the standard bore plus the 30 over measurement s a total so i know what to tell the machine shop here,

[OhioYJ]

valves are unshrouded,The valves are normally shrouded some by the cylinder walls, not just the heads themselves.