1971 / 1972 Engine Output Options On An Automatic?

[GCorvette]

I'm trying to establish what the best engine output options were available from the factory specifically for an automatic in 1971 and 1972.
After looking at different books and websites, i'm totally confused by what appears conflicting information.

Could anyone clarify for me please?
Thank you in advance.

 

[Nassau65]

The 350ci was available in 270hp or 330hp. Then of course the 454ci took it up to 390 and above. All motors available with automatic transmission.
I think the base motor was the 270hp version.

 

[GCorvette]

The 350ci was available in 270hp or 330hp. Then of course the 454ci took it up to 390 and above. All motors available with automatic transmission.
I think the base motor was the 270hp version.

Thank you.
I have seen mention of a 425hp available for the automatic in 1971.
Was that not correct?

 

[James Vette]

Just tune it to what you want.

 

[GCorvette]

Just tune it to what you want.

Of course, but I'd like to know the answer all the same.

 

[Nassau65]

I think the 425hp could be the another 454ci motor for that year. I know there was 2

 

[GCorvette]

I think the 425hp could be the another 454ci motor for that year. I know there was 2

I saw mention of an LS6 at 425hp (from the Chevelle line) & also a 350ci 425hp but am unsure if these were the same engine and were they available to autos?
Certainly the latter seemed to be if the information is correct...

 

[Oneball]

Top of the performance ranges were LS6 (BB) was 425hp with alloy heads (basically an L89) and LT1 (SB) was 330hp. Both big money now due to rarity.

 

[Nassau65]

Correct the 454 LS6 was the daddy of Chevrolet motors and famously powered the chevelle 454ci 425hp

 

[GCorvette]

Top of the performance ranges were LS6 (BB) was 425hp with alloy heads (basically an L89) and LT1 (SB) was 330hp. Both big money now due to rarity.

Thank you.

 

[Nassau65]

LT1 was available in manual transmission only. No auto

 

[Nassau65]

Both motors were big money options when new, even bigger now, due to rarity.

 

[Nassau65]

Frightening fuel consumption on a 454ci. Drinks more than a thirsty camel

 

[GCorvette]

Thanks for that gents.

So, the 64 million $ question...
Which engine would be better to have for torque on a driver car or would (as James said) it be better to modify an engine to get the best balance between torque and fuel economy?

 

[Nassau65]

Both the 454 motors will give horrendous fuel economy. People moaned about it back in 1971 and in theUS gas was 12 cents a gallon. The LT1 was only available with a manual transmission. So the 350/270 with a auto and a bit of special tuning may be the answer.

 

[GCorvette]

LT1 was available in manual transmission only. No auto

So the LS6 at 425hp was the top auto option?

The 350/270 with a auto and a bit of special tuning may be the answer.

Any recommendations as to what would add specific amounts of hp?
In addition, without having to rebuild the rear end, do we know what the hp the engine could be safely taken to on an auto?

 

[Nassau65]

Teamzr1 would probably be the man to advise you on that me thinks.

 

[GCorvette]

So the LS6 at 425hp was the top auto option?

Any recommendations as to what would add specific amounts of hp?
In addition, without having to rebuild the rear end, do we know what the hp the engine could be safely taken to on an auto?

@teamzr1 Are you able to kindly advise as suggested by @Nassau65 ?
I read somewhere on a forum the driveline can take about 350 hp without significant upgrading?

 

[Nassau65]

Yes, 454ci 425hp was the top/most expensive engine option. It filled that engine bay up nicely.

 

[Roscobbc]

So the LS6 at 425hp was the top auto option?

Any recommendations as to what would add specific amounts of hp?
In addition, without having to rebuild the rear end, do we know what the hp the engine could be safely taken to on an auto?

OK, so mines a manual so a different set of potential 'abuse' issues - but I am running more HP (and importantly torque) than any high output 454 or perhaps even the legendary L88 engine (albeit at lower rpm's). The drive train is 100% stock - other than clutch. The rear end ratio is 3.08. Rear tyres additionally with 285 mm section have far more grip than any 1970's options (other than perhaps slicks).
I can report that I am still running all the original drive line components - all this with a very real and genuine engine dyno figure of 571 bhp and 606 ftlbs torque.
However - I never do a 'rev and drop the clutch' type pull aways. I do not do rolling burn-outs. It is this kind of treatment whether in an auto or manual that kills driveline components. Even something simple like ironworks on the carriageway allowing one wheel to spin-up momentarily (and then grip) can play havoc with driveline components.
As to whether an automatic transmission is 'kinder' on driveline components I'll leave for you to consider. Torque multiplication of the converter may well increase stress on components.