Trying to put a converter out of a 66 Skylark with a 300 v8 and a st300 tranny. Im trying to use it with a st400 that I'm marrying to a 401. I was under the impression it was a simple bolt and go, but its appearing like there might be a slight size difference with inner converter the numbers of the st 300 converter are 626 ( some symbol) 296 and 28 sp6. the 400 converter slides right on, but the 300 seems like smaller grooves. has anyone else experienced this?
I put a 67 st300 converter in my 67 sp400 in the convertible. The 300 converter is 1 inch smaller than the 400 and gives more stall in the hi and low pitch range. Also its lighter due to smaller size! Its a poormans upgrade for a mild built engine! Seems like it didn't just fall right into place but it was a pain. Once in it has done fine
http://www.v8buick.com/index.php?threads/vp-converter-trans-visual-id-guide.143723/ Not all ST300s were switch pitch.
The '66 st300 was a switch pitch. Only the 65 and 66 Nailhead st400 trans were a switch pitch, the 64 was not. The smaller converter has different mounting bolt locations than the larger st400 converter. Some 401-425 flexplates are drilled for both converters, some are drilled only for the larger converter. The '66 300 converter should fit as long as it's a 65-66 st400 trans. It is a nice upgrade.
they've got different shafts, and the 300 only has one electrical prong on the side, while the 400 has 2. suddenly Im not sure if the 300 is a switch pitch.... :-(
The 4th picture is a switch pitch input shaft, the 5th is a fixed pitch input shaft. The difference is in the stator splines. The SP stator splines are 1/2 the length of the fixed pitch splines. Like I said, not all 300's were switch pitch. If it came out of a 66, it should have been, but how sure of that are you? It could also had been converted sometime in the past, but that is less likely.
