Ive gotta bore my open deck sleeve block to 85mm. Ive done a lot of research but most result were atleast 10 yrs old. Times have changed LOL My question is will i be ok with 85mm boosting atleat 20-25 psi on a 67mm? Looking to make 550-600 whp. Thank you!

 

Most will recommend not going much passed 84mm and 85mm being the absolute largest without a doubt. The gains are minimal and not worth the risk involved. Most would be more concerned about headgasket sealing above all at 85mm and boost. O-ring may be your friend here.

 

Ive made 600hp on 85mm open deck with O-ring. Im sure others will post their experience.

 

1100ish HP here at 85mm, but I use a SS o-ring.

 

Thank you all for your responses! Unfortunately my sleeved block is not O ringed. However i did speak to my machinist this afternoon and asked if he can o ring it. He said yes but its risky because of the limited space between the sleeves.. Then again after a quick research look like most o ring 85mm blocks have limited space between each cylinders! What to do? HMMM!

 

GE O-rings at 85mm. You're going to spend a lot of money paying a machinist to setup tooling for the Oring than you would shipping it to a shop that does it on a daily basis. Get a quote first.

 

Look at Muckman's build thread for decent pics on how the O-rings will overlap. You can do firgure 8 style or half circles. The choice is yours!