tranny for 68 chevy pu

[ksuwildcats2004]

Hi all just joined today . my name is roger im 54 and live in ks.I have a 68 c10 chevy with the new process 435 tranny . It is stuck between 2nd and third gear and cant get it to free up. I can get the top cover lifted up about a inch or two but can not get it to come off. my understanding is it has to be shifted in the reverse position to come off. any advice on getting it unstuck so i can shift it .The syncros had been acting up for awhile before it got stuck so I dont think it is anything major that caused the hanging up .Also this tranny has the granny gear for first, is there another tranny that will bolt up and have a higher top end. Thanks in advance. Roger