I am mainly a V8 man, but i have a 67 mustang which came as a six cylinder.
I ran the deal on a dynojet chassis dyno.
The six has many mods done, but i was suprised at the output.
145 HP at the wheels is like 180 @ the flywheel.
For 204 " that isn't bad, considering the old school cylinder head.
Ran my 67 mustang with the old engine 4-11-09.
Temperature was 73 degrees F & @ 45' above sea level.
Engine is a 204" engine with a 274 camshaft & a holley 4412 carb with annular discharge nozzles direct mounted on a 80 modified head with 1.6 roller tip rockers. See my profile.
video & audio of run
A/F was 13.2 WOT
The dyno is a new dynojet unit.
I wish i could have run the 1.65 yella-terra full roller rockers.
Because of an oil leak at the lr of the engine i had to remove them.
In the future i will block the oil supply to the head by plugging the oil galley at the left rear of the engine.
The engine was definitely stronger with the 1.65 rockers.
I bet i lost at least 5 HP by having to go to the 1.6 roller tip rockers to releave the full oil pressure at the headgasket sealing area.
The 274 cam has served its purpose & now i am ready to step up to a very aggressive camshaft which will require valve springs in the 140# seat pressure area.
The log head hopefully will respond to a more aggressive camshaft by camshaft innovations for more power.
The secret is a matched combination of componets & the present camshaft & the head are limiting the full potential of this engine.
To use the CI head with valve lifts in the .570" area it will require longer valves for a higher spring height for the increased lift & clearance between the retainer & the valve seal-guide area.
When the CI head was designed no one ever thought of using valve lifts in the .570" area.
Overall i am very satisified with my power results.
If i richen the mixture to say 12.8 i may loose 5 HP but will gain 5-10 ftlbs of torque.
Only track testing will be the final answer. Bill