how big is too big?

[Jeepjunky]

new to stroker motors but not to xj's, i was just wondering with the 4.0L block, what would be the maximum u would recommend on bore size.

when i eventually get around to building a stroker, i want to know exactly what im guna do

also approximately how long it would last, mileage wise.
i was personally thinking a bore of 3.955 (go big or go home), with 4.060 crank, 4.2L conrods, bulltear pistons dished 30cc's--- would this setup be able to run on regular unleaded gas or have to run premium

thanks

[4.whoa]

IIRC the biggest I've seen so far was 306 ci. Don't remember the bore vs stroke but its on here somewhere. There are considerations with max boring. You SHOULD sonic check before going more than .060 over. Depending on what you're going to do with it you don't want thin walls especially with boost/ nos.
Longevity is anyone guess(I'm sorry to say) more so when you max it out.

[gradon]

X2 on what whoa said. Diamondaic has a block bored .080" over with diamond forged pistons. .060" over tends to be the safe max.

[Cheromaniac]

You could go as big as a 4.00" bore but that'll leave the cylinder walls very thin so the block would need to be sonic tested. Combined with a 4.06" stroke, a displacement of 306ci or 5.0L is possible if you can find the right block but that's taking the 4.0 block beyond its design limits. Otherwise just stick to a maximum overbore of 0.060" (3.935" bore dia.) to be safe.

[92tank]

or you could see if you can find someone to bore and sleeve it, then you could go just about as big as you want