69 GMC with pont 455, have ?'s - The 1947 - Present Chevrolet & GMC Truck Message Board Network

mkmiller1 · 12-12-2002, 10:06 PM

Had a fella call me tonight that has a '69 GMC short step he put a '72 Pont 455 with the SUPER Turbo 350(says it has 4 forward gears) with 50,000 original miles on it that he wants to sell. He says it is 80% highway ready and 97% body ready. Says there is NO rust he just ran out of time and money(he's 60) and doesn't want to finish it. It also sits on a newer frame with disk brakes.

What do y'all think of the 455/ Super turbo 400 setup? He doesn't want very much at all for the truck and I'm going to look at it saturday. I just wanted a little info on this setup as I've never dealt with Pont/olds stuff before.
Thanks,
Matthew

WHYBYNU · 12-12-2002, 10:24 PM

mk, Sounds like something to check out I'm not much help on that combo. My parents live in Taylor, AR just down the highway from you. You live in truck HEAVEN down there 67-72 are everywhere. I was just was there in Sept. ( I live in Ontario NY). and talked to a guy in Springhill,LA with a 72 shortstep with 32,000 org miles his father bought it new. Good luck Sat. Let us know how it goes.

John

Longhorn Man · 12-13-2002, 01:25 AM

A super wha???
It is probably a TH400 with a lock up converter.
No such thing as a TH400 with 4 gears.
The 455 is an animal, and would be a fun ride.
Double check his work REAL close.

Duallie · 12-13-2002, 04:13 AM

He probably meant the super turbine (400?), a precursor to the TurboHydraMatic 400, introduced in 1964. From what I recall, it was a two-speed transmission with a sorta-switchpitch converter, giving four speeds. You won't find anyone who can rebuild it, almost guaranteed. Its ancient and inefficient technology. But then again, it may be a THM 400 and the old fart is calling it a super turbine 'cause thats what he grew up with.

Longhorn Man · 12-13-2002, 01:15 PM

I was under the impression that a switch pitch was nothing more than a converter in a normal TH400.
All the switch pitch was (if I'm not mistakrn) was a verter that you could chose one of two stall speeds. Hit the switch and you'll have 2500 stall, turn it off and it would be a 'stock' stall speed.
Andy one confirm/deny?

imaindianoutlaw · 12-13-2002, 04:13 PM

Your correct mail! But I have never heard of a SUPER th400? The 455 alone is worth $600 bills running atleast! I wish this truck was in pa, its what I am building! I hope you get this thing so I can get some pics of the drivetrain! If you get me the #'s off the block(just left of the water pump on the front side of the block) and the head code(on the center exaust ports) I can tell you what ya got!

imaindianoutlaw · 12-13-2002, 04:18 PM

72 had a limited amount of engines 17 different ones to be exact!
455 codes are as followed:

YH 7L4
YC 7M5
YA 7M5
ZH 7M5
WM 7F6
YB 7F6
WD 7F6
YE 7F6

LAST 4 ARE 300 HP UNGINES AND THE OTHER ARE 250 HP
ALSO THE LAST FOUR ARE 4 BOLTS HO ENGINES

GOOD LUCK!

imaindianoutlaw · 12-13-2002, 04:19 PM

The switch pitch trannys are rebuildable a man named jim hand uses them in his drag/driver cars for atleast the past 10 years

mikep · 12-13-2002, 10:05 PM

I used to run a switch pitch turbo 400 in a 69 camaro. Actually it was a chevy turbo 400 case with a toronado switch pitch converter, valve body , and pump. I dont know why they arent more popular. It was considered the hot ticket back in the early 80's. I had a microswitch hooked up to the carburetor linkage that would change the stall speed when I gave it full throttle. Same principle as the lockup converter but with performance in mind instead of fuel economy. It went from 1500 or so clear up to nearly 3000 behind the small block I had in the camaro. That car would smoke the tires all day long! Theres nothing to making a standard turbo 400 a switch pitch. You just need a donor oldsmobile or cadillac transmission to get the parts. Theres no diference in the steels , clutches or drums. Hell, I did it when I was 17. I will have to say that the switch pitch parts are probably getting a bit on the hard side to find these days.

Longhorn Man · 12-14-2002, 12:21 AM

On a Caddy board, some one stated that it could be a good idea to wire the verter to the brake lights. That way you could have a stock stall when driving it "like a normal person"...ie, one foot for brake and gas. Or when you wanna launch, (and using two feet) your brake lights would cause the stall to go up, and you could just keep your foot on the brake ever so lightly to keep the lights and the switch in the verter on.
Best of both worlds. I know I have been keeping my eyes open for one.

mkmiller1 · 12-14-2002, 11:24 AM

Thanks for the info! I'll let ya know what I find.
Thanks,
Matthew

mkmiller1 · 12-14-2002, 03:02 PM

I went.
I looked.
Bucket of rust, hack job!
Actually sat on a 77 short frame with the '77 bed, cab dash had been cut out and the pont dash installed, cab rusted in the normal places with rust in windshield frame. The motor ran really good and the tranny was the turbine 400(still called it a super turbo) shift indicator read PRNDSL. The engine codes by the water pump is YH 0310331. Had a pretty good GMC chrome grille and front bumper. Wanted $500 today or it's not for sale anymore(got some cash from somewhere else).
thanks for y'alls help,
Matthew

imaindianoutlaw · 12-14-2002, 05:50 PM

Go get it!

mkmiller1 · 12-14-2002, 07:03 PM

the problem is that I have no use for the motor or tranny. I know some members might, but I would need comitment before tying that much $$ up in something I can't use. Oh yeah, odometer read 53480.0 miles that are supposed to be original.
Matthew

imaindianoutlaw · 12-14-2002, 07:45 PM

This is a 69 gmc with a running motor and basicly rust free body and is a short bed! $500? You should be all over that! I dont see the problem? By the sounds of it I would be all over it for a $1000

larouchedem · 12-15-2002, 01:18 AM

Hello All,

Fyi - there are both 2 speed and three speed transmissions that have switch pitch convertors [called variable pitch by GM].
Here are what I believe to be facts;

Olds and Buick used the two speeds. Olds Buick
and Caddy used the three speed. Olds called the
2 speed a jet-away. Buick called it a super turbine 300. I'm sure they both had spiffy names for the 3 speed TH400 version, but I'm not sure what they were. '67 was the last year for the switch pitch [both 2 and 3 speed].

The TH400 switch pitch came in most, if not all '64-'67 Buicks, Olds' and Caddys. There are several bellhousing patterns and tail shaft lengths. '64-'67 Caddys were unique, as were the '64-'67 Buicks with the old nail head 401"
and 425" engines. All others have the later b-o-p pattern, afaik.

Although Pontiac also used a 2 speed, they never had the switch pitch convertor in either the 2 speed or TH400. The 2 speed lived on until the late 60s, but '68 and newer 2 speeds are not switch pitch. Note - The buick/olds/pontiac 2 speed is not the same as a chevy 'glide, although some people claim that there was a rare bop pattern 'glide.

The switch pitch TH400s used a 13" convertor. The switch pitch 2 speeds used a 12" convertor. The 12" convertor from the 2 speed fits the TH400 switch pitch pump. In a 3500 lbs car with good traction and a healthy engine, the 12" convertor will stall apx 2000/3000, and the 13" one will stall apx 1200/2500.
--

How to i.d. a switch pitch trans and convertor;

1. Look at the detent wire terminal. If it has only one wire, it is not a switch pitch for sure.
[see below].
2. Look at the front pump. The splines on the pump body are apx 5/8" long, whereas splines on a normal pump are apx 1.25".
3. Feel inside the convertor. Unless you have abnormally long fingers, you can not feel splines inside the switch pitch convertor, whereas you can feel splines inside a normal convertor.

Note on two wires - some 70s model TH400s had two wires, but they were not a switch pitch. The extra wire on those went to a pressure switch on the valve body that controlled emission equipment. The 2nd wire on a switch pitch goes to a solenoid on the back of the pump.

You can convert a normal TH400 to s-p, but some of the late TH400s can not be converted. Look at the number of bolts holding the pump into the case. If the case does not have as many bolts as the older switch pitch tranny, it can not be converted.
[see note below]. The older non switch pitch transmissions have the proper passages to convert them to switch pitch, but the later cases with lesser number of pump bolt holes do not.

Parts needed to convert;
1. Pump, including solenoid on back of pump.
2. Input shaft and or input shaft/forward drum.
3. convertor
4. small restrictor in a hole in the case at apx 8 O'clock looking at front of trans. This restrictor is a must, and must be used in the case that is being converted. The restrictor is apx 3/8" in diameter.
5. Electrical plug and wiring

Fwiw - a line lock botton or other momentary switch works well to control the stall speed. You can also splice into the brake light circuit to cause the convertor to go into high stall at the stop light. This helps if you have a lumpy cam and your engine would like a looser convertor when idling in gear. Note - if this is done, the break lights will be on whenever the momentary switch is used. A diode can be used to prevent the current from reaching the break light circuit when the momentary switch is closed.
Dave

>X< · 12-15-2002, 01:19 PM

sounds like deal just to get the motor. i have a 350 pontiac and would love to drive up to school with a 455, since all pontiacs look the same and bolt up the same. if you buy it how much would you take for just the motor? jsut wonderin

larouchedem · 12-15-2002, 02:15 PM

Hello All,

I forgot to mention that the fwd '66/'67 Toronado and the '67 Eldorado TH425 also used the switch pitch. The internal parts needed to convert to switch pitch can also be found in those transmissions as well. Same deal - two wires = sp. One wire = no sp ['68 fwd TH425 is not sp].
Dave

The TH400 switch pitch came in most, if not all '64-'67 Buicks, Olds' and Caddys. There are several bellhousing patterns and tail shaft lengths. '64-'67 Caddys were unique, as were the '64-'67 Buicks with the old nail head 401"
and 425" engines. All others have the later b-o-p pattern, afaik.

12-12-2002, 10:06 PM	#1
mkmiller1 Senior Member Join Date: Dec 2000 Location: Magnolia, Arkansas Posts: 1,091	69 GMC with pont 455, have ?'s Had a fella call me tonight that has a '69 GMC short step he put a '72 Pont 455 with the SUPER Turbo 350(says it has 4 forward gears) with 50,000 original miles on it that he wants to sell. He says it is 80% highway ready and 97% body ready. Says there is NO rust he just ran out of time and money(he's 60) and doesn't want to finish it. It also sits on a newer frame with disk brakes. What do y'all think of the 455/ Super turbo 400 setup? He doesn't want very much at all for the truck and I'm going to look at it saturday. I just wanted a little info on this setup as I've never dealt with Pont/olds stuff before. Thanks, Matthew __________________ GOD is good...All the time! '71 swb custom10 barn find-68K original miles 72 K5 CST rust bucket, but runs and drives 84K miles

12-12-2002, 10:24 PM	#2
WHYBYNU WHYBYNU when old will do Join Date: Feb 2002 Location: Hot Springs, AR. Posts: 647	mk, Sounds like something to check out I'm not much help on that combo. My parents live in Taylor, AR just down the highway from you. You live in truck HEAVEN down there 67-72 are everywhere. I was just was there in Sept. ( I live in Ontario NY). and talked to a guy in Springhill,LA with a 72 shortstep with 32,000 org miles his father bought it new. Good luck Sat. Let us know how it goes. John __________________ 71 Cheyenne super 2 tone green and white ZZ6 - Th350 4/6 drop 20x8.5 / 20x10 Billet Specialties

12-13-2002, 04:13 AM	#4
Duallie Registered User Join Date: Feb 2001 Location: Nikiski, Alaska Posts: 477	He probably meant the super turbine (400?), a precursor to the TurboHydraMatic 400, introduced in 1964. From what I recall, it was a two-speed transmission with a sorta-switchpitch converter, giving four speeds. You won't find anyone who can rebuild it, almost guaranteed. Its ancient and inefficient technology. But then again, it may be a THM 400 and the old fart is calling it a super turbine 'cause thats what he grew up with. __________________ Just as if I knew what I was doin'

12-13-2002, 04:13 PM	#6
imaindianoutlaw GMC SHORT FLEET F/S Join Date: Jun 2000 Location: SOUTH WILLIAMSPORT PENNSYLVANNIA Posts: 2,117	Your correct mail! But I have never heard of a SUPER th400? The 455 alone is worth $600 bills running atleast! I wish this truck was in pa, its what I am building! I hope you get this thing so I can get some pics of the drivetrain! If you get me the #'s off the block(just left of the water pump on the front side of the block) and the head code(on the center exaust ports) I can tell you what ya got! __________________ CHARLES WADE HEIN HVACR FOREMAN. LEWISBURG U.S.P.

12-13-2002, 04:18 PM	#7
imaindianoutlaw GMC SHORT FLEET F/S Join Date: Jun 2000 Location: SOUTH WILLIAMSPORT PENNSYLVANNIA Posts: 2,117	72 had a limited amount of engines 17 different ones to be exact! 455 codes are as followed: YH 7L4 YC 7M5 YA 7M5 ZH 7M5 WM 7F6 YB 7F6 WD 7F6 YE 7F6 LAST 4 ARE 300 HP UNGINES AND THE OTHER ARE 250 HP ALSO THE LAST FOUR ARE 4 BOLTS HO ENGINES GOOD LUCK! __________________ CHARLES WADE HEIN HVACR FOREMAN. LEWISBURG U.S.P.

12-13-2002, 01:25 AM	#3
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	A super wha??? It is probably a TH400 with a lock up converter. No such thing as a TH400 with 4 gears. The 455 is an animal, and would be a fun ride. Double check his work REAL close.

12-13-2002, 01:15 PM	#5
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	I was under the impression that a switch pitch was nothing more than a converter in a normal TH400. All the switch pitch was (if I'm not mistakrn) was a verter that you could chose one of two stall speeds. Hit the switch and you'll have 2500 stall, turn it off and it would be a 'stock' stall speed. Andy one confirm/deny?

12-13-2002, 04:19 PM	#8
imaindianoutlaw GMC SHORT FLEET F/S Join Date: Jun 2000 Location: SOUTH WILLIAMSPORT PENNSYLVANNIA Posts: 2,117	The switch pitch trannys are rebuildable a man named jim hand uses them in his drag/driver cars for atleast the past 10 years __________________ CHARLES WADE HEIN HVACR FOREMAN. LEWISBURG U.S.P.

12-13-2002, 10:05 PM	#9
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	I used to run a switch pitch turbo 400 in a 69 camaro. Actually it was a chevy turbo 400 case with a toronado switch pitch converter, valve body , and pump. I dont know why they arent more popular. It was considered the hot ticket back in the early 80's. I had a microswitch hooked up to the carburetor linkage that would change the stall speed when I gave it full throttle. Same principle as the lockup converter but with performance in mind instead of fuel economy. It went from 1500 or so clear up to nearly 3000 behind the small block I had in the camaro. That car would smoke the tires all day long! Theres nothing to making a standard turbo 400 a switch pitch. You just need a donor oldsmobile or cadillac transmission to get the parts. Theres no diference in the steels , clutches or drums. Hell, I did it when I was 17. I will have to say that the switch pitch parts are probably getting a bit on the hard side to find these days. __________________ No truck :-( Last edited by mikep; 12-13-2002 at 10:09 PM.

12-14-2002, 12:21 AM	#10
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	On a Caddy board, some one stated that it could be a good idea to wire the verter to the brake lights. That way you could have a stock stall when driving it "like a normal person"...ie, one foot for brake and gas. Or when you wanna launch, (and using two feet) your brake lights would cause the stall to go up, and you could just keep your foot on the brake ever so lightly to keep the lights and the switch in the verter on. Best of both worlds. I know I have been keeping my eyes open for one.

12-14-2002, 11:24 AM	#11
mkmiller1 Senior Member Join Date: Dec 2000 Location: Magnolia, Arkansas Posts: 1,091	Thanks for the info! I'll let ya know what I find. Thanks, Matthew __________________ GOD is good...All the time! '71 swb custom10 barn find-68K original miles 72 K5 CST rust bucket, but runs and drives 84K miles

12-14-2002, 03:02 PM	#12
mkmiller1 Senior Member Join Date: Dec 2000 Location: Magnolia, Arkansas Posts: 1,091	I went. I looked. Bucket of rust, hack job! Actually sat on a 77 short frame with the '77 bed, cab dash had been cut out and the pont dash installed, cab rusted in the normal places with rust in windshield frame. The motor ran really good and the tranny was the turbine 400(still called it a super turbo) shift indicator read PRNDSL. The engine codes by the water pump is YH 0310331. Had a pretty good GMC chrome grille and front bumper. Wanted $500 today or it's not for sale anymore(got some cash from somewhere else). thanks for y'alls help, Matthew __________________ GOD is good...All the time! '71 swb custom10 barn find-68K original miles 72 K5 CST rust bucket, but runs and drives 84K miles

12-14-2002, 05:50 PM	#13
imaindianoutlaw GMC SHORT FLEET F/S Join Date: Jun 2000 Location: SOUTH WILLIAMSPORT PENNSYLVANNIA Posts: 2,117	Go get it! __________________ CHARLES WADE HEIN HVACR FOREMAN. LEWISBURG U.S.P.

12-14-2002, 07:03 PM	#14
mkmiller1 Senior Member Join Date: Dec 2000 Location: Magnolia, Arkansas Posts: 1,091	go get it the problem is that I have no use for the motor or tranny. I know some members might, but I would need comitment before tying that much $$ up in something I can't use. Oh yeah, odometer read 53480.0 miles that are supposed to be original. Matthew __________________ GOD is good...All the time! '71 swb custom10 barn find-68K original miles 72 K5 CST rust bucket, but runs and drives 84K miles

12-14-2002, 07:45 PM	#15
imaindianoutlaw GMC SHORT FLEET F/S Join Date: Jun 2000 Location: SOUTH WILLIAMSPORT PENNSYLVANNIA Posts: 2,117	This is a 69 gmc with a running motor and basicly rust free body and is a short bed! $500? You should be all over that! I dont see the problem? By the sounds of it I would be all over it for a $1000 __________________ CHARLES WADE HEIN HVACR FOREMAN. LEWISBURG U.S.P.



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12-15-2002, 01:18 AM	#16
larouchedem Registered User Join Date: Nov 2002 Posts: 36	switch pitch info - long Hello All, Fyi - there are both 2 speed and three speed transmissions that have switch pitch convertors [called variable pitch by GM]. Here are what I believe to be facts; Olds and Buick used the two speeds. Olds Buick and Caddy used the three speed. Olds called the 2 speed a jet-away. Buick called it a super turbine 300. I'm sure they both had spiffy names for the 3 speed TH400 version, but I'm not sure what they were. '67 was the last year for the switch pitch [both 2 and 3 speed]. The TH400 switch pitch came in most, if not all '64-'67 Buicks, Olds' and Caddys. There are several bellhousing patterns and tail shaft lengths. '64-'67 Caddys were unique, as were the '64-'67 Buicks with the old nail head 401" and 425" engines. All others have the later b-o-p pattern, afaik. Although Pontiac also used a 2 speed, they never had the switch pitch convertor in either the 2 speed or TH400. The 2 speed lived on until the late 60s, but '68 and newer 2 speeds are not switch pitch. Note - The buick/olds/pontiac 2 speed is not the same as a chevy 'glide, although some people claim that there was a rare bop pattern 'glide. The switch pitch TH400s used a 13" convertor. The switch pitch 2 speeds used a 12" convertor. The 12" convertor from the 2 speed fits the TH400 switch pitch pump. In a 3500 lbs car with good traction and a healthy engine, the 12" convertor will stall apx 2000/3000, and the 13" one will stall apx 1200/2500. -- How to i.d. a switch pitch trans and convertor; 1. Look at the detent wire terminal. If it has only one wire, it is not a switch pitch for sure. [see below]. 2. Look at the front pump. The splines on the pump body are apx 5/8" long, whereas splines on a normal pump are apx 1.25". 3. Feel inside the convertor. Unless you have abnormally long fingers, you can not feel splines inside the switch pitch convertor, whereas you can feel splines inside a normal convertor. Note on two wires - some 70s model TH400s had two wires, but they were not a switch pitch. The extra wire on those went to a pressure switch on the valve body that controlled emission equipment. The 2nd wire on a switch pitch goes to a solenoid on the back of the pump. You can convert a normal TH400 to s-p, but some of the late TH400s can not be converted. Look at the number of bolts holding the pump into the case. If the case does not have as many bolts as the older switch pitch tranny, it can not be converted. [see note below]. The older non switch pitch transmissions have the proper passages to convert them to switch pitch, but the later cases with lesser number of pump bolt holes do not. Parts needed to convert; 1. Pump, including solenoid on back of pump. 2. Input shaft and or input shaft/forward drum. 3. convertor 4. small restrictor in a hole in the case at apx 8 O'clock looking at front of trans. This restrictor is a must, and must be used in the case that is being converted. The restrictor is apx 3/8" in diameter. 5. Electrical plug and wiring Fwiw - a line lock botton or other momentary switch works well to control the stall speed. You can also splice into the brake light circuit to cause the convertor to go into high stall at the stop light. This helps if you have a lumpy cam and your engine would like a looser convertor when idling in gear. Note - if this is done, the break lights will be on whenever the momentary switch is used. A diode can be used to prevent the current from reaching the break light circuit when the momentary switch is closed. Dave

12-15-2002, 01:19 PM	#17
>X< registered IWATA user Join Date: Feb 2002 Location: Baton Rouge Posts: 4,481	sounds like deal just to get the motor. i have a 350 pontiac and would love to drive up to school with a 455, since all pontiacs look the same and bolt up the same. if you buy it how much would you take for just the motor? jsut wonderin __________________ -'63 Ford Fairlane 500 coupe, v8, auto, faded and rusty. awaiting built roller 302 and some flat black -'99 Honda Prelude. vtech/5spd. no pipe, no intake, bone stock. awaiting new top end. -01 GMC Yukon SLT 5.3 dented and scratched with a noisy tranny. Take off that Von Dutch hat before i stab you with a 000 Mack.

12-15-2002, 02:15 PM	#18
larouchedem Registered User Join Date: Nov 2002 Posts: 36	more switch pitch info - Hello All, I forgot to mention that the fwd '66/'67 Toronado and the '67 Eldorado TH425 also used the switch pitch. The internal parts needed to convert to switch pitch can also be found in those transmissions as well. Same deal - two wires = sp. One wire = no sp ['68 fwd TH425 is not sp]. Dave The TH400 switch pitch came in most, if not all '64-'67 Buicks, Olds' and Caddys. There are several bellhousing patterns and tail shaft lengths. '64-'67 Caddys were unique, as were the '64-'67 Buicks with the old nail head 401" and 425" engines. All others have the later b-o-p pattern, afaik.

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