GM LS SBC combination slider with 4.155 ” ID bore diameter. With this slider you have two sliders in one, it works with LS engine like LS2,LS3 and SBC 265-400 CID engines. Made of 3/4″ thick 6061 aluminum with black anodized finish. Custom bore size add $75. (This is a made to order item 7-10 business days.) Please e-mail with questions.