So, my 1972 Cutlass 442 with the 455 engine was rated at 270hp from the factory. Just curious question for those more mechanically talented than I.....What would you guess the 270 hp 455 be rated at if the previous rating system were applied to the 1972 motor. Just curious......doesn't really matter but curious!

OLE442

 

No need to guess OLE442, it was 340 hp gross. The factory gave us both ratings in 1971.

Two sentences above the "more data" blue highlight below.

 

In '72, the V code 4spd 455 was rated at 270, the U code 455 was 250. Also, the '71 (442 455 340 gross hp) had the big valves while in '72 only the V and X codes got the big valves; The U code got the small valves. Cams were different, too.

 

Aah! I believe then that my “U” code automatic would be 250 hp and not sure what the gross hp would be then!

 

Jay, I am assuming the reason the 71/72 X code was only 50 hp apart gross to net on literature. Was because the X codes had less restrictions applied to them in order to maximize performance ? Or there was simply a more efficient way to cut back gross to net impact with a more expensive option ? Or were X codes underrated on purpose, and rather than 350/300 it was really 370/300 ?

Original road test at the time indicate identical performance between the 1970 and 1972 W30 Auto. And I mean identical, same exact options, same magazine, etc...

Quote:
Originally Posted by 69CSHC

Here is High Performance Cars November 1972 test result for the 1972 W30 AT, PS, PB, no A/C. 3.42 gears, G70-14 Tires. 14.37 @ 98 MPH

http://wildaboutcarsonline.com/membe...0_Test_1-4.pdf


Quote:
Originally Posted by joe_padavano

1970 W30

In the May 1970 issue, High Performance Cars tested that yellow 70 with the red stripes. AT, W27 rear, PS, PB, but no A/C. 3.42 gears, stock F70-14 bias ply tires. They ran a best of 14.30 @ 98 MPH.

https://classicoldsmobile.com/forums...e-time-166828/

There is a scenario where even a high performance models setup is not maximized to extract every bit of horsepower. Its possible the 1970-1972 W30 auto had identical performance because that's all the setup could touch upon. And when both are pushed to the enth degree the 70 will prevail.

 

Here’s a snapshot of my 1971 Owners Manual showing the engine specs. 1971 and 1972 engines were the same, but in ‘71 both the old and new ratings were listed.

 

OLE442, it's a little hard to make out on the chart but for 1971 the L32 455 was 320 gross and 250 net.

Here post #13 from Joe Padavano https://classicoldsmobile.com/forums...-330-a-160660/

 

That matches my personal experience back in the 80s between my 1970 350-4bbl Supreme and a friend’s 1972 350-4 bbl Supreme, both with 2.56 gears. Both cars launched and stayed side by side through 1st gear (almost 60 mph).

This was when I started questioning how a 1.75 point difference in compression ratio translated to a 50 horsepower difference.

 

Fun71 I find it interesting that the 1971 Owner's manual does not include the W30 at all. And states that the 270 hp was thee performance engine ...

Produced so early that the W30 didn't exist yet ? Or does a W30 get its own specific manual...

 

I don’t know which vehicles got the TT and TS code engines.

 

I believe you.

Personally although the 1971 conversion chart indicates there is a 60 hp difference gross to net on 4bbl dual exhaust 350. I believe the 310hp was overrated on automatic. My 310 was more like 235 in my opinion, and that is not enough to pull away from a 200 hp 72 350 supreme with the same gearing setup, at least early on in a race.

The stick version and its more aggressive cam was 250 net in my opinion. The autos were just lumped in by association. And the stick W31s 325 hp rating was legitimate to slightly underrated. Original performance was identical to the 1979 W72 400 T/A which was underrated, and truly 280 net hp. (Pontiac got away with murder in the 1970s besting Corvette over and over again while lying through their teeth.)

 

Wow, this is all so confusing to me! lol

 

No need for confusion. Phil answered your question in post 2.

The rest are just hi-jacks of your post by us car-guys who never miss a chance to talk about horsepower.

 

The 1970 'stick version'; would that be the rare 'early' version of the 350 that had a hotter cam that was around for a short time early in the '70 model year? I could see Olds using that early edition engine for their '310hp' rating, just a tick under the W31, and the later, more common 3504bbls seeming less than 310. I will say the all original Rallye 350 my brother had back in the late '80s ran Strong and not to much wimpy'er than his '70 442 AT it even Sounded almost like the exact same exhaust burble (both cars had original mufflers) Always thought it was the add'n of the W25 hood and good duals/trumpets that woke it up but wonder if it had that better cam, too?

Regarding the diff between high and low comp engines; our '70s seemed to have been a bit more responsive, etc. to our '72s (350 and 455s) but in retrospect maybe most of that was the 3:23 and 3:42 gears vs. the most-common-for-'72 2:73 rear? The comparison of the 70 and 72 W30 autos w/ac and their 1/4 mile times is believable (perhaps the 72 was given a good tune-up to correct the timing and carb changes. I can say that back in '86 or 87 I ran my '72 U code (w/ac) convertible at LACR at a (elevation corrected) 14.89 @ 89mph w/2:73 open rear! Only a good tune (plugs, BlueStreak points, cap, rotor, carb dialed in) and no mods so mid-low 14s for '72 W30 AT sounds right.

 

Thank you VC455!