twilightblue28A

Please explain the difference(s) between the "OG" and "OW" transmissions for the model year 1970. Thank you!!

svnt442

The calibration of the valve body and governor for shift points and firmness.

Rocketbrian

As stated above the valve body differences plus the biggest difference is the 6 disc direct clutch drum vs. a 5 disc for the OG.

My442

The torque converter is different.

Stall speed is higher and it has 6 log mounting, vs. 3 lug mounting on the others.

twilightblue28A

Thanks for your assistance. The valve body is calibrated for different shift points, five (5") vs six (6") direct disc drum, and a five (5") three (3) lug vs a six (6") six lug torque converter. What is the practical difference in performance especially since the 365 HP has the same cam as the 370hp in 1970? I appreciate your knowledge.

twilightblue28A

And as a seperate but related issue, I installed the 4 speed cam in my car and my car died. My elapsed time (ET) for one quarter mile increased by 1.2 seconds (best) and my mph barely broke 100mph.

OLDSter Ralph

370hp auto or 370hp SMT ? I think the 370hp auto was delivered from the factory with 286 degree .474" lift cam, same as 365hp, but the 370hp SMT used the 328 degree cam. The 328 degree cam was legal in the auto and stick classes that used the 370 HP power rating in NHRA.

twilightblue28A

Sorry for the confusion I caused. My question is what practical performance difference does the "OW" transmission make especially when running the W30 engine, automatic transmission, which utilizes the same cam as the 365 HP with automatic transmission?

70Post

What do you consider a "practical performance difference" to be....


>The "feel" of the trans? ie - shift hardness?, shift RPM point under full throttle?


>Or...differences in 1/4 mile performance that are measured in very small fractions of a second? (and only when the rest of the "combo" has been tweaked to take advantage of any changes - ie - better tires to take advantage of a higher flash stall speed in the converter, etc).


Did you degree the new cam when it was installed?


Is it REALLY the cam the seller says it is?? Reason I ask this is a good friend on here bought a "repro" cam (same cam "application" that you refer to) and then checked it on a Cam Doctor device only to find out the specs were nowhere near the original cam it was supposed to be a copy of. Bought from a very well known Olds parts vendor.


What about other parts of the car?? Carb tuning to be more specific....Rochester built a different carb for the 4 spd cars VS. the automatic cars. GM was all about "saving production costs" so ask yourself..."Why did they have 4 different carbs for '70 442's and W30's?"

jensenracing77

The OW also had different apply pistons in them. It was a minor difference but was specific to the OW. Not sure if all the clutch packs but I think all of them had an extra disc in them.

VC455

The records I've seen, including the parts books, show a unique cam for the 1970 442 SMT. It was part number 406768 with advertised duration of 294° - 296°.

My 1970 SMT 442 had that cam.

1969w3155

yes that is correct, but Oldster Ralph noted the 370hp SMT, which was the W30 4spd in 1970, not the 442 4spd. Different cams.

OLDSter Ralph

The .294.296 cam was probably the correct cam for a 4-4-2, and I assume the 365hp engine. The 328 degree cam was probably listed as 4-4-2 OAI or something.
I believe that .294/.296 cam was also used in the 1969 H/O ?


Thanks for the clarification, I stand corrected.

joe_padavano

In 1970, the manual trans W-30 got the 328/328 cam. The automatic trans W-30 got the 285/287 cam, which is exactly the same cam used in every other AT 442 that year, along with the W-32, W-33, and W-34 motors. The only differences between the AT W-30 motor and every other AT 442 motor were the heads (F vs E), carb ('258 vs '251), initial timing (10 deg vs. 8 deg), and mechanical advance curve. Frankly, I don't see a lot of difference between the AT W-30 motor and the run of the mill AT 442 motor that year. I bet that if you made the jetting and timing changes to your AT 442, it would run exactly the same as an AT W-30.

OLDSter Ralph

Joe, I should have noted in my post SMT 4-4-2 for 294/296 cam that VC455 was referring to in his post. I am sure both engines were under rated (365 HP and 370 HP).


I think they figured W-30 AT buyers would also want power brakes and the 328/328 cam was not good for that in an AT.

twilightblue28A

Thank you again for responding. In my original post, I requested an explanation of the difference(s) between an "OG" and "OW" transmission for a 1970 automatic 442 W30. I received several responses acknowledged in my post number five. Did an "OW" transmission respond differently compared to an "OG" transmission. Firmer shifting? Increased performance? Faster ET? What was the practical effect of an "OW" vs an "OG" transmission? And if there wasn't increased performance with my "OW," why were the "OW" transmissions installed instead of the "OG" transmissions? Thank you again.

oldsmobiledave

Did I miss the part about the W-30 455 getting an AL intake vs iron on the other 455s?

twilightblue28A

I agree the W30's had an aluminum intake manifold. I'm seeking a response to post number 16. Thanks again.

joe_padavano

Yeah, OK. Memory's the second thing to go and I can't remember the first.


Of course, the runners were exactly the same as those in the iron intake, so no performance improvement other than lower weight.

OLDSter Ralph

I added the aluminum intake to Joe's statement in BOLD font in post 15. I am sure his mind was faster than his fingers. I should probably have noted the addition to Joe's answer in my post.