I'm beginning my project for my B18A1 boosted on 8-10psi. I'm keeping the bottom end stock other than balancing the rotating assembly and getting the connecting rods shot-peen'd. I'm trying to keep the compression at or around stock LS comp. ratio(9.2:1)..

So my questions/concerns are that I want to get the head worked on to increase the airflow as the LS heads are the weakness to all B18A/B's. I plan to oversize the exhaust valves by 1mm and upgrade the valves/springs/retainers. I'm not sure that if getting the head ported and polished would up the compression ratio? Any feedback would be appreciated thanks.

 

if your going to upgarde valvetrain and cams then do somethign with the bottom end. the engine will make power on a stock head. id invest in a stout bottom end first ie pistons/rods and leave the head stock. the weak link in the ls is rod bolts and ringlands on the pistons.

porting and polishing an ls head is a waste of money, Just adding an agressive cam and valvetrain ie springs retainers is all that is needed, anything else is a waste and wont net much power gains for dollar value

eagle rods, with some good pistons 81.5mm bore, valve springs and retainers with some jg303 or crower 404 cams and you will be happy so long as your running a good manifold and dcent turbo otherwise will be cam overkill on a cast log and a small turbo

if you can find yrou self a b18b head, th b18a heads had smaller ports and wont make as much power, heads are a dime a dozen for an LS