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Yo, any help deciphering this 455 block would be appreciated. This is currently a swap-in to my 68 442 conv.. This is what all of my interneting has produced:
3- Oldsmobile
8- 1968
C- ?
Buncha numbers
What's that extra stamp? If zoomed in, you can see an additional stamp toward the bottom right of the tab. Never seen that before. Any ideas?
If there was a photo, it didn't post.
The interwebs work under the assumption that Oldsmobile only built A-body cars, so info on other models is sparse. C is the Southgate, CA assembly plant, where full size cars were built. The remaining six digits are the sequence number from the car it was born in.
If there was a photo, it didn't post.
The interwebs work under the assumption that Oldsmobile only built A-body cars, so info on other models is sparse. C is the Southgate, CA assembly plant, where full size cars were built. The remaining six digits are the sequence number from the car it was born in.
Makes sense. I didn't get a good shot of the three digit stamp located in the lower right hand corner of the derivative stamp tab. Maybe I'll grab another pic later today. It's a hard angle to see with the bracket in the way. The top of the stamp is visible in the pic. I'm thinking it may be a re-stamp of the original stamp's last three digits?
I think the answer is no, but is there any way to narrow down the car it was born into with this number? South Gate was pretty prolific apparently.
I have the current vehicle vin but no other information on factory setup. As I said, the engine is a swap sometime in the 80s. The transmission mated is the TH375.
Did 68 442s come factory w/TH375 transmission or did the transmission go in with the 455 to make it fit in the 68 without having to change the drive shaft?
Southgate built full size cars in 1968. The engine came out of an Olds Delta 88 or a Ninety Eight. It could have been an L60 low compression 2bbl, an L66 high compression 2bbl, or an L31 high compression 4bbl. No way of knowing what it was originally without tearing it down and looking at the pistons and cam. Every 1968 442 with an automatic got a TH400, an OG code for most 442s, an OH code for the 2bbl 400 Turnpike Cruiser, and an OW code for the W30 and H/O. All TH375s were long tail transmissions. Is that what you have? They were only used behind the 350 in the Vista Cruiser and the Delmont 88 that year. They would have come with an OA code. Also note that the TH375 tailhousing has a "TH375" cast into it.
Southgate built full size cars in 1968. The engine came out of an Olds Delta 88 or a Ninety Eight. It could have been an L60 low compression 2bbl, an L66 high compression 2bbl, or an L31 high compression 4bbl. No way of knowing what it was originally without tearing it down and looking at the pistons and cam. Every 1968 442 with an automatic got a TH400, an OG code for most 442s, an OH code for the 2bbl 400 Turnpike Cruiser, and an OW code for the W30 and H/O. All TH375s were long tail transmissions. Is that what you have? They were only used behind the 350 in the Vista Cruiser and the Delmont 88 that year. They would have come with an OA code. Also note that the TH375 tailhousing has a "TH375" cast into it.
Yes, it's clearly labeled a TH375. TH37ll be pulling the motor and trans out this fall after the second snow storm. Looking forward to seeing what I have. Can I swap in a different auto transmission without too much retrofitting?
The TH375 uses the small diameter output shaft and is longer than the correct short tail TH400 for that car. You'll need both a different front yoke and a longer driveshaft to do it correctly. The TH375 is a light duty version of the TH400.
By the way, it would be interesting to know if the VIN derivative on the trans matches the one on the engine. As far as I know, the TH375 was only used by Olds behind small blocks in long wheelbase cars, but if it matches that 455, it might indicate this is the L60 low compression 2bbl motor.
By the way, it would be interesting to know if the VIN derivative on the trans matches the one on the engine. As far as I know, the TH375 was only used by Olds behind small blocks in long wheelbase cars, but if it matches that 455, it might indicate this is the L60 low compression 2bbl motor.
I'm going to guess it's a low compression 2bbl. Interestingly, the p/o I bought it from gave my a real nice 4bbl rochester(29251RJ 3538) and oem 455 cast iron manifold, but is currently configured with a 2bbl setup. Rebuilt the 4bbl carb, was going to refinsh the 4bbl manifold and throw it in next week.
With your excellent info, I may just drive it with that ridiculously small looking 2bbl until the engine/tranny pull this fall. Maybe do some upgrades to the engine and put in a different(beefier) trans..
I really appreciate the info. I was super glad to find that, even though not original, the engine is a 68. Not that it matters much, but i like the idea of it for myself.
I guess the id on the heads might give up the info on high or low compression? Cam id maybe as well? Doesn't that thing look so silly on that giant hunk of metal. It's like a lawnmower carb.
Still good for, oh, 300 or so HP. Along with 455 torque.
Turbo 375s. Mmph. A 375 is a lighter-duty 400. A 375B is a heavier duty 350. And depending who you talk to a 425 is a FWD 400, or a RWD 400 beefed up to go behind a 454 Chevy. I've had Chevy guys argue that with me for years.
Still good for, oh, 300 or so HP. Along with 455 torque.
Turbo 375s. Mmph. A 375 is a lighter-duty 400. A 375B is a heavier duty 350. And depending who you talk to a 425 is a FWD 400, or a RWD 400 beefed up to go behind a 454 Chevy. I've had Chevy guys argue that with me for years.
Thanks for the info. I'll certainly keep that in mind.
I guess the id on the heads might give up the info on high or low compression? Cam id maybe as well? Doesn't that thing look so silly on that giant hunk of metal. It's like a lawnmower carb.
If I remember correctly L60 and L66 came with the same cam and small valve heads, the only difference was the pistons. If you have the air cleaner it might give you a clue, the L60 came with a black air cleaner housing and the L66 came with the orange/red air cleaner. I was able to confirm the pistons on my L66 with a bore scope camera. Did you check for a forged crank yet?
I guess the id on the heads might give up the info on high or low compression? Cam id maybe as well?
Olds varied compression by changing the size of the dish in the piston, not the heads. As I said, you need to tear it apart to know for sure. A borescope in the spark plug hole might give you an idea of the size of the dish. I suspect that most 425s built in the 1965 model year were 2bbl high compression L66 motors. By the way, the big block Olds motors got a special 2GC carb with larger bores and throttle blades than did most 2GC carbs.
Olds varied compression by changing the size of the dish in the piston, not the heads. As I said, you need to tear it apart to know for sure. A borescope in the spark plug hole might give you an idea of the size of the dish. I suspect that most 425s built in the 1965 model year were 2bbl high compression L66 motors. By the way, the big block Olds motors got a special 2GC carb with larger bores and throttle blades than did most 2GC carbs.
Awesome! Always wanted a borescope. I am thinking I might just leave the current setup til fall. Done a ton of work over the past 3 months. I wanna throw it all back together and drive it for the next few months. Excited to test out the new brakes/steering/suspension work as well as sit in those newly upholstered pearl white seats. Hell, with the air cleaner on, which is a 2bbl BLACK air cleaner, only Olds fellas like you folks would know it's a two barrel.
I'm looking forward to pulling and wrenching on the motor. Seems likely its the low compression build. No big deal. Its a fun mystery to unravel. Especially with you guys willing to share knowledge. Thanks again.
