I have a 1965 Skylark, 300 V8. The block is a cast 65 w/ 64 aluminum heads and intake. The motor is punched 0.30 over, high rev lifters, dual valve springs, high volume oil pump, 25hp over stock cam, headers and 2.5 inch exhaust backed by a TH350 (shift kit and stall converter). Right now the trans modulator is set so that it religiously shifts at 4000 RPM. I'm thinking that I should be able to bump this up a touch. Does anyone know what the redline would be for the 300 V8 (even if you only know the stock motor specs)? I just want to at least have a benchmark to work with when I adjust my modulator. Is 5000 RPM too high to have the trans shift? I appreciate anyone's input. Thanks, Matt
I'm by no means any type of expert.... ...... but I would think that 5000 is definately not too high of a shift point, especially in a small block. I would expect that it would go over 4000 right from the factory? (at wide open throttle) o No: Don't take my word on it though.. wait for someone who knows what they're talking about. :gt: :beer :laugh:
Matt, Adjusting the modulator does nothing for your WOT shift points. That is controlled by the governor. The modulator will alter your minumum shift points and feel(only 2-3 MPH) That is what you should adjust the modulator for. Do you have the kickdown cable hooked up and adjusted correctly? It also has some effect on your WOT shift points. To access the governor, look on the drivers side of the trans, behind a circular cap(secured with a wire clip-same type as used on a master cylinder cap) Remove the governor and disassemble it, and lighten the inner weights a little at a time for higher WOT shift points. Reassemble and install the governor and roadtest. It is very time consumming. B&M sells a shift point modification kit for the 350 and 400. It comes with an assortment of weights and springs so that you don't need to grind on yours. There is a thread on this in the gears forum, check it out for more info. Good luck.
What part of CT are you from? As far as breaking something 5k is no problem. Since your's is all rebuilt then you'll have no problems getting there. When I first got my 350, if I held it in first it would break-up real bad right around 5k. After the cam/valvesprings/ new lifters, and stuff, it got up to more than 6k no prob.
I'm going to try and address a few of the posts here at once. I'm from South Windsor, CT - and thanks for your input! Larry, I was told by a local tranny shop that I have an adjustable modulator which would regulate when the trans was shifting. They told me to remove the vacuum line and with a small screwdriver that fits in, I can move the screw inside clockwise to advance the shift point and counter clockwise to retard the shift. In fact they told me not to open that round cover. Now don't get me wrong, I'm not telling you that I think you're incorrect, but rather posting this OPPOSITE opinion for your comments. In fact I invite your opinion. Auto trans' are pretty foriegn to me and I just want to figure out the right way to adjust it. Thanks, Matt
Matt, Your trans uses 3 inputs to determine shift points at different throttle openings. Modulator(vacuum), detent cable(throttle position), and governor(vehicle speed). All 3 must be hooked up and adjusted correctly. They interact with one another to get the right shift points under varying conditions. The modulator is adjustable, but only 2-3 MPH at most. At full throttle, vacuum is close to 0, the modulator increases the line pressure for a harder shift. The governor has the most to do with full throttle shift points. Adjusting the weights and springs is necessary to alter your WOT shift points. You should aim for a WOT shift at 5000 RPM. Try posting in the juice box forum, you may get more responses there. I don't mind being questioned at all. I'm pretty sure I'm right here though. Good luck.
