I have a Chevelle with a 250 Inline and 350 turbo tranny I run down the drag strip. I leave in "Drive" and hold the throttle wide open. The tranny does not shift out of first gear until the car is going about 40 mph and does not shift out of second gear until about 50 or more. By this time I am closing in on the finish line and am only in third gear a very short time before I cross the line. I would like to make the shift points much sooner but the problem is if I leave the line in Low gear and upshift the car manually it does not make any difference, she still shifts on her own like she does when I leave the line in Drive. Is there any way I can do something to this bone-stock tranny to make it shift on it's own at a pre-determined speed (or rpm) of my choosing with the car in "Drive" or if not can I adjust the tranny to shift immediately as I manually move the shifter from low to second and then from second to third?
Thanks, Ken B
When your foot is on the floor( WOT) is why it shifts at them points Not matter if you try to do it Manually or not. You may change the Vac. modulator to a ajustable one and see if that will help. But with WOT those shift points are about right. But hope this helps.}[oooooo]
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NovaMan/Twisted6/Larry
Without putting in a manual valve body, the trans will shift when it feels like it. What you really need to do is think about using a different rear end with lower gears. The idea is to choose a ratio (and tire diameter combination) that will allow your engine to be close to redline in 3rd gear when you cross the finish line.
I know that's an expensive proposition, but that's drag racing. But then again, if you're bracket racing, then consistency is what brings home the trophys. You can use whatever you've got as long as you know how long it takes and what the dial is.
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David
newbie #4153
I have a TH350 in my street rod and I put in a shift kit from Transco that I bought from Summit Racing for less than $ 100.00. It will allow you to shift transmission manual or automatic. It works great. Comes with video and complete instructions and color coded parts... DAVE
If you manually shift at a lower RPM, your times will probably be worse. They surely will not be any better
I THINK THAT I READ AN ARTICAL ABOUT THIS IN SUPER CHEVY LAST MOUNTH AND THE B&M TRANS PEOPLE HAVE A KIT TO ADJUST THE SHIFT POINTS IN THE TH350 & TH400 AND SOME FORDS ALSO. I WILL TRY TO FIND IT TOMORROW.
MIKE...
the mag story was in CHEVY HIGH PERFORMANCE MAG AUGUST 03, PAGE 62--66 THIS IS WHAT I THINK YOU ARE LOOKING FOR. GOOD LUCK KEN.
MIKE...
You must change the govenor spring to make the tranny shift at different points. I had to do the same thing in my street rod. Find a tranny shop that has a variety of springs and that will let you try them until you find the ones that work. The adjustable modulator helps to fine tune the shift points but won't make a big difference
I just went thru this drill with my 500 caddy / turbo400 rear eng. dragster;I bought the B&M kit and then hit some local tranny shops and collected all the stock weights I could find, and 3 govenor bodies to work with.look real close, there are 3 different top plates
(high,med and low) and they do not interchange, match the one in your trans. read the instructions... build the spares with the weight/spring combos from 1 to 3 steps different from the stock setup.(I started with the lightest weights and the strongest springs, and in 4 steps went to the heviest stock weights with light springs)Now, off to the strip...I started with short squirts (330 ft)only and watched the 1-2 shift RPM. (the 2-3 will be within 200 RPM of the 1-2) leave the vacuum modulator alone for now.(it works only for part throttle shifts anyway)you will see a big change in the RPM, and can then mix and match. put the shift point to the test with a full pass,It didn't help to mess with the outer weights,(I tried 3 different sets)but one inner weight and spring only was a winner for my setup. with some combo's the trans would shift 1-2 ok but not go to high gear.(bangin' the rev limiter just ain't fun in a 1250 lb car...)others would shift 1-3 skipping second. don't give up, the right combo is in there!that's why I built 4 complete govenors, I got so good at changin' them out, I was swappin'em in the stagin' lanes. (lol, my fingers still look like french fries) when you lose those little "C" clips that come in the kit,(and you will!)cut up some coat hanger wire about 2.250 " long and bend a short,sharp 90 deg, in one end. a slight bend in the other end will hold it in place and make it lots easier to change things. B&M will not sell those pins and clips separate (rat's)