bbc clearances

Ron Gusack · 11-18-2015, 08:43 PM

My buddy's engine is coming up a little tighter than I've been.
Drag only 427+.030 bbc with GM 1077 aluminum heads, steel rods, older Manley 12.5 pistons turning 7300 tops.

Piston is out .003 and he wants to use a .039 compressed gasket. Piston to wall clearance is .005 -.007, is this quench too tight?

He has loads of piston to valve clearance except radially. He used clay and has .030-.040 at the center of the piston, where the little triangle is. Too tight?

Thanks for any help

11-18-2015, 08:43 PM	#1
Ron Gusack Member Join Date: Feb 2009 Posts: 244 Likes: 1 Liked 7 Times in 6 Posts	bbc clearances My buddy's engine is coming up a little tighter than I've been. Drag only 427+.030 bbc with GM 1077 aluminum heads, steel rods, older Manley 12.5 pistons turning 7300 tops. Piston is out .003 and he wants to use a .039 compressed gasket. Piston to wall clearance is .005 -.007, is this quench too tight? He has loads of piston to valve clearance except radially. He used clay and has .030-.040 at the center of the piston, where the little triangle is. Too tight? Thanks for any help