disapoining et

Cover the fundamentals before throwing parts at it. Assuming it runs clean without missing or popping...

Compression and leak down test?

Valve train right if adjustable rockers?

Dist curve correct?

Plus/wires/dist cap and rotor all good?

Cam in at the right CL?

Is the carb getting full throttle????

Exhaust system a cork??

With that MPH, I doubt if it's spinning the tires, just is down on power. So find it...that combo should be in the mid 12's easy peasy.