i'm searching through posts as i type this on HT, TI and SH. my question is more in regards to stress and mpg than anything else. right now i have an 81.25mm bore b18c bottom end with the forged mahle pistons set at .0035-PWC and ARP rod bolts. ACL race bearings setup at .002 on the rods and .0022 on the mains. that should be loose enough to work well with moderate boost. without a block guard or sleeves where is the safe limit with boost in longevity? i hate throwing out random numbers but somewhere in the neighborhood of 270-290whp seems do-able without a lot of work. another concern is the motor being at 10:8-1 compression. the top end is fairly simple with a ported p72 casting, ferrera 6000 valves, honda yellow springs and crower 401 cams with a blox IM and ITR TB.

 

your compression is on the edge, just get a good tune and it should be ok. might want to consider a thicker headgasket to lower it a little.

mpg has alot to do with the tune and driving habits. in my boosted car (b18, gt30r, 880cc) i got almost 30mpg if i stayed out of boost, but if i got on it mpg would obviousy suffer.

longevity also goes back to the tune. you have a pretty stout bottom end, 500+ hp has been done on stock sleeves but thats pusing it