TwistedEvo8

i have a b18a1 block with 140587 miles on it i plan on tearing it down and rebuilding it everything with new internals for boost im not sure on what machine work i should have done to it so it can handle 300hp no problem. should i even worry about boring the cylinders out to 84 or just leave em as is. any suggestions would be great.

jdmadam

You dont need that much of a bore for you power goals. You can leave the bore the way it is and just do your internal upgrades for boost. If you do decide to bore it, I recommend you bore to 81.5 which is just .5 over the stock bore.

Fabrik8

Boring the cylinders isn't going to help you handle more power. It might make it easier to produce more power, but boring doesn't add anything to strength at all. I'm not really sure which one you're asking about...

z31kid

go .50 over and get a good piston and rod combination..300hp can easily be made with the right combination.

TwistedEvo8

i thought it would be to much them walls would be as thin as a penny don't think that's good for boost. thanks fellas for your input.

Gen_Crunchytoes

Do not bore the stock sleeves, if you really want an 84mm block have it sleeved to 84. But to reach 300whp you don't need to increase the bore size at all. A simple t3/t4 setup will get you to your goals