I was just reading a thread that said the 305 LB9 locks up at as low as 20MPH and the 350 L98 locks up around 40MPH. But on my L98 350 TPI my TCC is locking up at around 20 MPH in drive or over drive. I was wondering if someone might have put in a 305 computer or maybe the 305 prom. How can I tell if they have changed either one or both of these. Im pretty shure I have read that the computers are the same on both the 305 & 350 only the prom is different but im not shure. If anyone knows how to tell the diff in the proms let me know plese & if my TCC shouldnt be locking at shuch a low speed. I have the 165 ecm also.

Take the cover plate off the ECM and see what the four letter code on the chip is.That will identify what is was originally for.
Nothing to say someone has not modified the tune on a stock chip though