12:1 compression 351 Winsor with AFR heads in a 1966 Mustang. It's a back half car running with a C4 transmission with a Trans brake. During rebuild signs of detonation were found, he had been running C12 racing fuel. 

Modifications were limited to the grooves and the squish clearance was opened to 0.070". Initial testing at the track was stopped because of violent wheel standing.  The grooves combined with the wider squish clearance eliminated a low RPM detonation problem. The resulting torque produced  violent  wheel standing delaying initial testing….

  

Glenn now has his chassis modified to handle the additional torque, with a higher gear in the rear-end he is now able to release the transbrake with out scraping the rear bumper.

Detonation is history, ET and RPMs are down; he sends his thanks to Somender