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Ed Wright · 03-20-2016, 11:58 AM

With mynaluminum SBC (LT1) heads, intakes are right at .005", exh more like .003", as the exhaust valve runs much hotter than the intake, making up for some of the head growth. With greater mass of a BBC head, I would think the difference would be greater.

I have run my intake valve-to-piston clearance as close as .036", using "checking" springs. Nothing touched, but no carbon formed where the valve would have touched. I normally use .040", but you had better have everything right, and stay on top of your springs. I would not try that with stud mounted rockers.

03-20-2016, 11:58 AM	#4
Ed Wright Veteran Member Join Date: Mar 2005 Location: Sand Springs, OK Posts: 8,132 Likes: 896 Liked 390 Times in 170 Posts	Re: Iron BBC w/ aluminum head growth With mynaluminum SBC (LT1) heads, intakes are right at .005", exh more like .003", as the exhaust valve runs much hotter than the intake, making up for some of the head growth. With greater mass of a BBC head, I would think the difference would be greater. I have run my intake valve-to-piston clearance as close as .036", using "checking" springs. Nothing touched, but no carbon formed where the valve would have touched. I normally use .040", but you had better have everything right, and stay on top of your springs. I would not try that with stud mounted rockers. __________________ Ed Wright 4156 SS/JA Last edited by Ed Wright; 03-20-2016 at 12:22 PM. Reason: Forgot something....