I have a 70 stage 1 trans and I am considering converting it to a switch pitch (I have a donor trans) and just need a confirmation that this can be done. I know that I will need a S.P.converter and switch as well as the case restrictor plug. Will this change over affect the regular operation other than the dual stall? Any thoughts?
Bill, you'll need the following: VP converter VP pump w/VP solenoid VP input shaft Case orifice Dual terminal case electrical connector Means of activation Depending on if you choose to use the ST400 converter or smaller ST300 converter, you may find low stall is a few hundred rpm lower than what you're used to in a fixed pitch converter. If that causes problems with idle quality, you then may want to activate high stall at idle like the factory did. Other than that you should notice no other changes in operation. Hope that helps... Devon
Hi Devon, I knew I forgot about something. Pump and shaft assem. Will shift quality still be there? 3 to 1? Idle quality is already poor so SP convertor should help.
The shift behavior will stay the same as you'll be retaining the original "BB" valve body. You'll love it, by the way! Devon
I have the high stall activated off of the brake light switch. As Devon said you will love it.:TU: Bob H.
This TransGo kit worked great for me before I converted mine to full manual: http://www.transgo.com/products.php...d=159&countdisplay=2&start=0&addcountview=Yes There are two other TransGo kits available that accomplish more: http://www.summitracing.com/search/...ansmission-shift-kits/transmission-type/th400 Devon
Get the 400 1-2 kit from Trans go, drill the A and B orifices to .110, pink spring on the regulator valve, no springs on the 1-2 accumulator valve in the valve body, and omit the big 2-3 accumulator spring under the piston. Use a red stripe vacuum modulator. if the clutches aren't a mile wide in the trans, it will provide a quick shift you have a hard time feeling at light throttle, but will chip the tires at WOT if you have enough grunt and gear in it. Adjustment of the vacuum modulator will give you the right shift feel and timing under light throttle. You should also put the big snap ring on the intermediate clutch that comes with the kit. I have the modified 300 SP converters available. Good luck JW
Ken Lisk, There are a couple of those on the shelf; not much demand this season. The factory control only worked at idle or near full throttle. Mine was developed to increase drivability on the street, in the mid range where most driving happens. It has torque sensing and timers for smoother shifts, fewer downshifts, and more zip. There is one "maximum performance" mode available. I'll post the flow diagram here; however, it probably makes a lot more sense when your are driving, than just reading it. Bruce
Thanks Bruce, I was actually able to follow that fairly well! I would be interested in one to go with the converter Jim is building for me. Could you PM me with cost, etc.? I don't want to hijack the thread. Thanks!
Ken, I have Bruce's SP controller. I have found that the high stall of that 12" converter is too loose for my taste when starting out from a dead stop. Bruce's controller in it's as delivered state has no way to reduce the time from "brake on" high stall to low stall below 3.2 seconds. As a result, when you release the brake to accelerate away from a stop, the converter is in high stall for no less than 3.2 seconds. I sent my controller back to Bruce and had him modify it so that it would go directly to low stall after you released the brake. There are other timers built into the box for drag racing. Those you can adjust, but for street driving, I found that modification helpful. You may want to consider that. I detailed all this in a thread sometime ago. Here it is Ken, http://www.v8buick.com/showthread.p...-Controller&highlight=Bruce+Roe+SP+controller
The starting point here was a great cruiser, with 13" converter and 2.41:1 axle for low rpm and economy. The switch pitch restored a lot of performance while maintaining (maybe even increasing a point) fuel economy. A by product was much smoother operation. The car gets to all 4 borders from time to time. If your care for none of that, instead racing, there may still be a controller mode to suit. There are other, simpler ways to control a drag car converter. Bruce Roe
