71OldsCut

Hi,

It isn't overly important at this point, but I keep coming across conflicting information about the engines that came with a 1971 Cutlass. Some sites say the 350 4 barrel has 260HP but others are saying 160HP. Anyone know what is right? I actually just found one claiming 310HP factory out of the 350....

Also wondering about the rear gear. It doesn't appear that posi was an option but wondering if someone could confirm that too...

Thanks!

Fun71

1971 was a transition year between the SAE GROSS ratings and the SAE NET ratings. My 1971 Owners manual lists both ratings for the 350-4bbl engine. Sorry, I don't have the 2bbl ratings but that's probably the 160 hp spec you saw.

350-4bbl Gross ratings:
260 hp @ 4600 RPM, 360 ft-lbs @ 3200 RPM

350-4bbl NET ratings:
200 hp @ 4600 RPM , 300 ft-lbs @ 3200 RPM



In 1972 the NET ratings were more accurate based on the which exhaust setup was used. Note that the engines were identical between 1971 and 1972, so these could be applied to the 1971 engines as well.

350 2bbl single exhaust: 160 hp @ 4000 RPM, 275 ft-lbs @ 2400 RPM
350 2bbl dual exhaust: 175 hp @ 4000 RPM, 295 ft-lbs @ 2600 RPM

350 4bbl single exhaust: 180 hp @ 4000 RPM, 275 ft-lbs @ 2800 RPM
350 4bbl dual exhaust: 200 hp @ 4400 RPM, 300 ft-lbs @ 3200 RPM

71OldsCut

Ok, good to know. I will take those numbers over the 160 that kept poping up on some sites. Wasn't aware of that being the transition year either.

Fun71

And yes, posi was an option that unfortunately many people didn't pay for.

71OldsCut

Interesting. Maybe a small burnout is in order then to find out.... lol. I suspect it is not, but I want to know.

joe_padavano

There is absolutely no confusion about this, it is all spelled out in the 1971 SPECS booklet. As noted, in 1971 Olds listed both SAE Gross HP (the old rating method) and SAE Net HP (the new rating method). Net was a lot closer to reality. The HP and torque ratings are part way down on this page. Note that 260 was the SAE Gross rating for the L74 4bbl motor, which was SAE Net rated at 180 HP for single exhaust and 200 HP for dual exhaust. The L65 2bbl motor was 240 Gross, 160 Net with single exhaust, and 175 net with dual exhaust.





I have no idea why you think posi was not offered. RPO G80 Anti-Spin rear axle was available on every single RWD Olds offered in the 1971 model year.

71OldsCut

I mentioned that it appeared it wasn't an option because of the information I was coming across all of it was how to add it and nothing on cars having it stock. This will be helpful.

JohnnyBs68S

That 310 HP rating for a 350-4bbl was GROSS HP for the high-compression '68-'70 engines with ~10:1 compression ratio. In '71 the compression ratio dropped to ~9:1, which is why it was rated for only 260 gross.

Consider that the 200 HP NET rating for that same 9:1 350-4bbl compares favorably w/ the (pathetically low) ~7.3:1 CR '76 Pontiac 455 that was rated for the same NET HP, but more torque. Not bad for a 100 CID disadvantage.

71OldsCut

Indeed, I agree. It is just something fun to drive around in for now, and 200+/- net horsepower is enough for that. Can always do an engine rebuild at some point with some performance parts down the road if we decide that is something we want to do.