Match Race ~ 1968 Road Runner '383' vs. 1966 Mercury Cyclone GT '390'

1966 Mercury Cyclone GT 390

Cylinder Heads
* Style .......................... Low-Riser
* Casting # ................... C6AE-R
* Intake Port Size .......... 2.34" x 1.34"
* Exhaust Port Size ........ 1.84" x 1.28"
* Combustion Chamber ... 63.60 {Minimum}
* Combustion Chamber ... 67.0 to 70.0 {Factory}
* Intake Valve ............... 2.037"
* Exhaust Valve ............. 1.560"
* Valve Spring {Closed} . #95 lbs.
* Valve Spring {Open} ... #255 lbs.

* Generally good flowing 'street performance' Cylinder Heads.
* Some restriction thru the Exhaust Ports.