My car has a probuilt 700r4, shifts great overall, the only problem ( to me) is it shifts @ 5000rpm on the 3-4 shift- the car is right at the HP peak for my combo, but if it could rev to 5500 rpm it would pull to about 105 mph before it goes into OD. this would make it fast enough to beat up on most things. if it could rev to 5800 before it kicks down to fourth that would be even better. I'm missing out on some speed here.

Basically I want it to rev out third more before it shifts. the TV cable is set right, it drives great- the governor is set up with very light wieghts and springs, don't know how much lighter is possible. the car will be very fast if it can just pull a little longer in third before it hits the overdrive 'wall'

ps- it shifts great in the lower gears, how can I change this to shift later in third only- should I call Dana?

 

Just put the shifter in D instead of OD. That way it wont shift into overdrive.

 

I know, it's just cool when every thing is maximized, and adjusted so all you have to do is floor it and kick but until it runs out of RPM, then hits OD automatically. makes impromtu races as easy a possible for you to take it to the other car

 

Mine does the same thing and also in the 2-3 shift at WOT. I to would like the car to automatically shift at 5500 instead of 5000. I would rather not try to manually shift it but have it do it automatically. Allen

 

Well ****, mine shifts @ 4500

 

mine shifts kinda late.. past 6400.. but thats just a overpowerd motor beating up on the stock tranny..

 

I thought with the stock valve body, and governor, the tranny should kick down at 5500rpm. Dana @ probuilt said it is mainly a function of the governor. I already have really light weights and springs. I guess I'll have to call him to see what he recommends. Still is best when an auto does what you want it to. Oh yeah, my 2-3 is @5000 too, I'm talking about the 3-4 , it shifts close to 5K@ about 95mph, I want it to rev to 5500 to take advantage of the extra rpms of my set up(vortec -hotcam) the car will pull still- if it could shift @ 5500 @ about 105mph that would be alot better- cop cars with 700R4's I heard (When the cops used cars with 700's) would kick down at 120mph into OD. so basically they could rev the crap out of third- thats how they could catch the bad guys- or chase other sports cars and still keep up with things that had much more power. I don't have proof - just remember reading articles about the mods to police cars , and one of the few things was a transmition, and computer that had none of the factory speed limitations- otherwise like a BC4 they are mostly stock.

 

removing one secondary spring will usually result in 500 rpms increase in engine rpm before the ratio change.if the 1/2 is already at 5500 then you must stiffen up the 2/3 shift valve spring or you will have a 6000rpm 1/2 and a 5500rpm 2/3 if it changed at 5000rpms before from 2/3.the spring modification will sometimes call for the addition of weight to the primarary side of the governor so mid throttle upshifts at 45 degrees throttle angle arent delayed.

 

Thanks for the info, this could be what I need to get to where I want the shifts to be. I need to confirm with Dana, I guess he said these wieghts that I have were normally used for a 60's chevelle and are already very light. I guess it's due to how he set it up for my car, I whish I know the details, sounds as if your very knowledgeable on the subject.

 

MY 91B4C CAME WITH THE VETTE CAM AND PISTONS, UPGRADED INJECTORS, AND MANY MORE UPGRADES FROM STOCK. tHE TRANS WHEN LEFT IN OD AND FLOORED WILL RUN TO 6250- 6300 RPMS IN EVERY GEAR BEFORE IT SHIFTS. WITH A 3.23 REAR YOUR 3-4 SHIFT IS A LITTLE OVER 115-120 MPH. (VETTE VALVEBODY, SERVO AND APPLY PISTONS)