I have a slightly beefed up motor in a 67 about 425hp with a "66" model c4 in it I also have an aftermarket hurst shifter in it, so heres my problem, I do a lot of manual shifting from stoplight to stoplight - I pull it back to first manually take off shift it manually to second alls good but then it gets to around 4000 rpm and shifts by itself to third so i loose a lot of power once I let of the throttle it bounces back into second by itself. I have been thinking that if I change out the valve body to a 67 or later version it may correct this cause of the whole green dot 64-66 c4 valve body do-hicky- is this true or do I have to go to a manual valve body or am I on the wrong track any help would be appreciated .. Thanks

 

K.......if you don't want to use a manual valve body, use a Trans-go -3 kit. It turns it into a manual valve body......SSsssshhhhh!!!!! Don't tell anyone I said that cuz I used to work at B&M........

 

I dont mind using a manual valve body if thats what I have to do but I would of liked it to work in auto still if poss. I heard that the only reason this is happening is due that the 64-66 c4 was designed to work that way but the 67 and later valve bodies werent and will hold in 2nd until you put it back into drive

 

Use the Trans-go -2 kit if you keep the early valve body. It'll allow you keep it in gear to almost 6500. The governors on the C4's like to override the valve bodies control even though it is still in the lower gears. I like "our" blower on your pic!!! Kinda still wish B&M kept it, I didn't want to move to KY.

 

thanks for the advice I'll give that a try...