Can someone explain to me the difference between the 70 olds 350 engine. I thought all the engines for that year horsepower was at 310, but I read some people say their cars have 250 horsepower. Basically I want to know which version has 310 hp.

 

Probably the 4 barrel, manual trans version with the hotter cam and dual exhaust. Remember those were gross numbers, the pathetic cam in the 350 cost power. The W-31 put out what 360 hp gross, big cam goes a long way.

 

From the powertrains booklet for 1970:

 

Nope...

 

All of the 4bbl versions (except the W-31) were factory rated at 310 horsepower. Don't believe that is a realistic number, though, as the factory used a blueprinted engine with no accessories or exhaust system to get those numbers, which are SAE GROSS ratings.

An example of the difference between GROSS and NET ratings can be seen on the 1971 350-4bbl which is rated 260 hp GROSS and 200 hp NET.
Then in 1972, the engines were rated differently for single exhaust and dual exhaust versions.

 

Why what does it put out? It is NOT 325 hp, there are reliable sources that say otherwise.

 

From what I remember of one of the Daves (don't remember which one) posting about a dyno run way back when, it did indeed put out 325 hp @ 5400 RPM. He said it kept increasing in HP as the RPM increased and they stopped at 6000 RPM for some reason but it was still increasing up to that point. But you are correct, seems I remember it was around 360 when they shut it down.

 

If you are talking about actual as opposed to advertised HP, I don't disagree with you. It wasn't clear from your post. Same thing with the 1970 W-30 MT cars that were actually demonstrated to put out about 440 HP vs. the 370 rating.

Don't confuse this with the weaker AT W-30s, however...

 

Speaking of early 350. Is there a way to determine if its a 2 or 4 barrel engine? w/o tearing into it? #'s say its a 68-70 350, it has a 4 bbl. intake but it also has # 8 heads.

 

You mean besides looking at the intake?

Seriously, the differences are CR and cam. I guess a borescope in the spark plug hole would give you an indication of CR. This is really your only option for 68-69 motors since both 2bbl and 4bbl used the same 250/264 deg cam. In 1970, the 2bbl motors and 4bbl AT motors kept that cam while 4bbl MT motors got the 286/286 deg cam. Note that I have excluded the W-31 motors, since those obviously got different CR and cams from either of these.

 

Since it has #8 heads I didn't want to bank on the intake being original?
Its coming apart anyway just my quest for info couldn't wait! LOL
Thanks Joe!

 

Yes, Joe I meant actual gross horsepower. We know the tiny cam auto 350 eould be very lucky to see anywhere near 310 hp. Now the manual trans cam 350 would be much closer. Look at the Vin Y vs the Vin 9 307. There is a 30 hp difference and the cam would be a good chunk of that. The Vin 9 cam is basically the 350 manual trans cam.

 

What number says it's a 68-70 engine? The 395558 2 casting number? If so, the info you got was wrong as that number was used on all 350s from 1968-1976. So with #8 heads it is likely a 73-76 engine, but you can always look at the VIN pad on the block. The second number is the year of manufacture.

 

I'll double check. #'s written down at home. Could kill my buzz. LOL Thanks!

 

Buzz killed. Its a 74. ah well. 180hp oh boy!
low compression=turbo time LOL

 

Joe
How does a borescope in the spark plug hole give you an indication of CR?
Thanks

 

It lets you see the size and depth of the dish in the piston.