There's nothing to bolt them to. Trick Flow Twisted Wedge Track Heat Heads, don't have the holes on the back of the heads like regular Trick Flow Twisted Wedge Heads have. Trick Flow Track Heat upper and lower intake, with 1 inch phenolic spacer, Trick Flow Twisted Wedge Track Heat aluminum heads, custom ground solid roller cam, Pro M MAF with cold air kit, calibrated for 30lb. injectors, etc. etc. 3028lbs. with my 205lb. a$$, anymore. You know I can't give away all my secrets, well one more Cervini 4" cowl hood and Cervini deck lid. Mike, ITLRUN