Probably going to be flamed for this one but here goes.

Is there any reason why the exhaust sleeve locating pins can't be removed by drilling the Ali housing away above them, then when replaced the area rebuilt with chemical metal? Reason being the 20b in my Cosmo still has the stock sleeves in place that i wan't to replace but compression is good and the motor running well so i didn't want to strip the engine just yet.

Kevin