197 13/15/18 Degree SBC Adapter Plates

18 deg. SBC adapter plates. Adapts an 18 deg. GM factory type bolt pattern to an 18 deg. spreadport Reher-Morrison pattern allowing up to a 2 1/4“ tube to be used in the header flange

THESE DO NOT WORK FOR THE STAHL PATTERN OR ANY 23 DEGREE HEAD OR HEADER FLANGE