Do I need to bore over 30 to put in pistons?

['68OrangeSunshine]

A 250 L6 @ stock stroke bored .030 over has 254 cubic inches.

[truckdude239]

the only reason i bored my 305 30 over is because in case it ever gave up the ghost i will be able to bore again

[GREASEMONKEY72]

Originally Posted by truckdude239

the only reason i bored my 305 30 over is because in case it ever gave up the ghost i will be able to bore again

thats the exact reason why you shouldnt go the max on the first time out, never know if youll have to bore it again

[RustyParts]

Have 'em throw on the torque plates while your at it, makes for nice straight cylinders.

[LMN8UR]

Typically blocks are cheaper than good pistons. So if you bore to the max and something fails, you'll have to replace the block and rebore. If something goes wrong and you damage a piston, you'll probably not have a block either.

There are a lot of theories out there. . Start with the machine shop, decide from their.

[Billla]

Originally Posted by Blue71LWB

I'm thinking of putting in some flat top pistons in my inline 250. I feel the engine is fine , but I was told I would need to have it bored if I was going to go with new pistons. I really don't want to bore the block. So will it be OK , to put in new ones without boring ?

Pistons come in different oversizes - .010, .020, .030 and so on. Somtimes there is an .002 or .003 piston as what's called a "high limit" piston - allowing a new piston to be installed after a quick flexi-hone if there's minimal bore wear.

It all starts with a bore measurement - the bore determines what your options are. Once the largest bore size is known, then you know what your options are. Sometimes the inline 6's show little or no bore wear even after 100's of thousands of miles.

['68OrangeSunshine]

I've got Badger pistons in my 292. My machinist set me up with them. They are cast pistons. If you want forged pistons you have to go to Arias or Ross, but they're spendy. You might get a line on them at www.inliners.org.
TRW doesn't make them anymore.

[PanelDeland]

I would go minimal overbore as suggested.The first thing though is to determine what you can get in the way of pistons without going custom.The options may be limited and could play a part in your decision.Since the 250 hasn't been built in many years there may not be as many choices since the demand has dropped.I also agree on a better cam,the cam reps will be able to help you more on that,make sure to have as many of the specs to give them as possible.Use good qulity head gaskets since the standard compression ratio is about 8.00:1 and the new will be higher.You may also need to run a better grade of fuel(higher octane)since compression will be higher.Since you are going to a 4 barrel you will want a better exhaust also maybe headers or a split manifold.