cause i tried punching the gas and it wouldnt go past 75

 

Then something is wrong. I bought a NEW 1983 Berlinetta with a 305 LG4 and 5-speed in 1983. I watched the white speedo needle go beyond the 85-mph marker, past the high-beam indicator and into the orange field (kph) a couple of times. That means I was probably going over 100-mph.

 

WHASSZZAAPPP...What happens when you hit the 75MPH mark? Does it bog, sputter, backfire, etc.? OR does it just feel like the fuel flow has been temporarily cut off? Will it come back on strong and cut back off again at 75 every time? If so, it sounds like a limiter. I remember reading an article in Car & Driver about these editors that bought three clunker cars for undr $1000 (a Berlinetta, a RX-7, a Golf) and the Berlinetta had some kind of problem limiting it from going as fast as the other two. JONESIN!!! Anyway, you could also contact HYPTERTECH...they should know. They enabled me to bring my '89 RS pas the limited 115MPH. Just FYI, although the Berlinetta in Car & Driver couldn't keep up with the two imports, it was the only one that could successfully ford a river!!! WHOOOOO!!!

 

Why would you want to go over 75MPH in a 1983 LG4 Berlinetta???
That car should labeled "Unsafe at any speed". Maybe thats why it has a 85 MPH speedometer.