i bought a 89crown vic from a guy that has e7te stamped on the block that is equipped with roller lifters 302 firing order, forged small dish 0 valve relief pistons, and efi system. the original factory heads were '86 stamping that are heart shaped combustion chambers which aka quenched, or closed for higher compression, which is only meant for a raised compression ratio over the 87 heads which were bigger chambered, and also this bigger chamber created lower compression and in all reality equals less power.BUT the 87s had bigger exhaust runners with big chambers thats good for blower or turbo i think the small combustion chamber with smaller exhaust runners in the quenched chambered heads made for better torque specs. the e7s were more for horsepower i would guess
The E6 head's chambers look smaller, but they're also deeper, with 4 more cc's volume than the E7 heads. Looks can be deceiving. And the exhaust runners are the same for both. The reason the E7 heads make more power on top is due to the chamber shape, the valves aren't shrouded by the chamber walls like they are in the E6 heads. To illustrate what I mean by deeper chambers, pull an intake (or exhaust) valve from each casting and you'll find that the E6 valve is shorter by about 1/8"
I have an ’86 mustang engine in my car with those heads and a carburetor-headers-duraspark and am relatively pleased with the performance. The car only has a 3.0/1 peg-leg rear axle and will easily pull a greased string from a cat’s ass. Results are not so good with a dry string.
Your results are due to the E6 heads producing more bottomend torque, combined with the 3 to 1 rear gears. The 86 HO Stang actually did produce better 1/4 mile times over the 87 due to this.
