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CNT
03-13-2002, 11:51 AM
On a 2.5 Merc., should the chamber be around 31cc's to get 145#? Anyone know how to caculate the amount to mill heads? (Say from 40cc's to 31cc's for example)
Jay Smith
03-13-2002, 08:40 PM
Most 2.5's at 31cc's with thin head gaskets will render 155 to 160 lbs of compression , a bit much for pump gas !

My opinion !

Jay @ JSRE
NPW
03-13-2002, 09:12 PM
35cc's will put you at 135 lbs,31cc's about 155.. 33cc's should be about max on pump gas at 142/145 lbs with thin gaskets..
us1
03-13-2002, 09:17 PM
Around 33CC depending on the deck and porting.