1966 Impala SS

[bigdawg5565]

Does anyone know what transmission went into the '66 Impala SS that had a 327 in it? I am looking at buying one this weekend and it appears to be an all original car, but I thought I read somewhere that the '66 Impala SS with the 327 had the powerglide. This car has a 3 speed auto. Any help or web location for more resources would be greatly appreicated. Thanks.

[MrPbody]

Can't say for sure about the small block. I did know a man with a '66 SS396 (Impala), and it had TH400. Most of the books say only PowerGlide.
Look at the pan. If it's shaped a bit like Texas, it's a 400. If it's rectangular, with one corner lopped off, it's a TH350, and is a transplant.

[bigdawg5565]

I am going to look at the car on Sunday. I printed off the transmission pan identification chart. I suspect that the original transmission was a powerglide and was replaced, but on the off chance that GM actually did in fact put in the TH350 with a smallblock it would be kinda rare I suspect. I guess everything right now points to a replacement transmission. I asked the owner if it was a two speed or three speed and I was told it was a three speed. I'll know for sure after I get a chance to look at the shift indicator and the transmission pan. I was also wondering if anyone knew of any online reference site's I could look at. Thanks for the help.

[molhannah]

here's some info I found about the vin # on the front of the block;
F – engine assembly plant – Flint, Michigan.
0821 – engine assembly date – August 21. Note: Since this Impala was built 05C – May third week (1966), this assembly date would be 1965 so all the casting numbers on the engine would have to be ‘pre’ August 21, 1965.
GF – engine suffix code – 1966 Impala 283 195 hp, Powerglide transmission, RPO (Regular Production Option) L-32, single 2 barrel carburetor with air conditioning.
also my interchange manual shows powerglide for impala's thru 1967

[MrPbody]

As I said, the books say "PowerGlide" exclusively, yet I know of at least 2 '66s with TH400 (both big block cars). I don't know the production dates of those cars. One of them, I know for sure, was original. The other I can't say.
There is no doubt GM did NOT put a TH350 in there, as '69 was the first year of production for TH350.

[ImportBuilder]

My 66 has a 2 speed Power Glide, but its not an SS. My dad had started to make it an SS clone and im not sure if the trans is part of the cloning or not...

[DPelletier]

I know I'm mostly repeating MrPBody and Molhannah's posts, but I thought I'd chime in anyway.

Both my '67 Impala SS 327 cars came with the Powerglide (although my convert ended up with a TH400 swapped in).
I would say two things are relatively certain;
- There were no TH350's in 1966, so if that's what's in there, its definitely been changed and
- I know of no small block TH400 equipped '66 or '67 Impalas.

I strongly suspect the car came with a 2spd glide and someones swapped in a TH350 or TH400.

Any new info?

Dave

[Keesee]

GM definitely produced Hydra Matic transmissions before 1969. The early transmissions ('65 & later) had a long tail housing and output shaft. These were designed as bona-fide three speed units and considered an early design TH 400. They were used with GM big block cars like Olds 98 (425 ci) Buick (430ci) Pontiac (421ci) Cadillac (472ci) and 396 Impalas. These cars were readily identifable by having 3 detents in the shifter selector mechinism and 3 forward "gears" marked on the shift indicator.

These transmissions could be swapped into a Chevelle, GTO, etc. by moving the complete transmission mount rearward on the frame rails and having the drive shaft shortened.

All cars with Powerglide transmissions had a 2 detent shifter and the letters "D" & "L" for Drive and Low marked on the selector. A tell tale sign of a tranny swap would be to try and move the selector to the position that would hold the transmission in low (1st.) gear without allowing it to upshift. Powerglide shift selectors did not physically have enough movement to allow this without modification to the selector.