Why does there seem to be so much confusion on factory ratings? Example: 1985 TA with TPI. I have seen it claimed to be 205hp, 210hp, 215hp. The Pontiac ad on this web site has it at 210 - I would guess I would use their number before the others. 205 I found in my 'standard catalog of Pontiac' book - but this book is an editing nightmare anyway. Why even give stats if they are going to be wrong so often?? 215 is the number used on the drivetrain chart on this site. I have found these numbers in many other place as well. Did Chevrolet publish different numbers and people have mushed them together and use the ones they like better? I still have not found where Pontiac claimed 245hp and 345ftlbs on the 5.7.

 

Correct me if im wrong(and someone is bound to), but in 1985 depending on what trans you got, that determines your horsepower. I believe if you have the t-5, you got a 10-15 hp advantage over the 700-R4. i also know this was the year of the "good" cam in the LB9.

 

Speaking for 1985 only, the TPI only came one way - with an automatic. The manual was paired with the L69 4bbl. I believe this applies to both Chev. and Pont. divisions.

 

The 85 brochure and press release both list it at 210hp. IMO anything else is wrong. The 215 you see is more than likely someone thinking the TA and Z28/IROC had the same hp rating, but they didnt. Supposedly the loss was due to the restrictive air intake setup on the TA. That sorta disappeared after 1985, even though 86 and 87 had the same intake as 85. Go figure.

As for the silly 5hp differences, from a performance standpoint its not worth arguing about. And I totally agree with you, if you are going to be publishing numbers at least have the appropriate research/paperwork to back it up or just leave it out.

 

Yeah, you're going to find that the FBirds with TPI are going to have lower numbers because of their intake.

 

"The 215 you see is more than likely someone thinking the TA and Z28/IROC had the same hp rating, but they didnt."

Am I correct to assume that this is the case in most model years? Is this why my 5.7 issue is this way. The camaro gets higher rating in the advertising because it is a Chevrolet marketed car. Did the last 5.7 third gen camaros have a 245hp rating? I know the Pontiacs didn't.

 

The reason for the difference is in my previous post why the Chevrolets numbers were a little better than the Pontiacs.

Also, the 92 350 TPI Camaro had 245HP, the FBird, 240HP.

 

Also, the numbers in the Tech Data section of this site are ALL Camaro Specs.

 

What pieces are different?

 

The air intake. The Camaros is a much better and less restricive design.

 

From the rubber boot in front of the throttle body to the air filter is where the 2 cars differ. The HP ratings were not always different between the two cars though, sometimes they were the same. Thats GM for ya.

 

The differences lasted through the MAF and MAP years? What was the reason for the different parts?

 

Reason the Firebird had lower HP numbers then the Camaro was the Firebird's lower hood design restricted the location of Intake.
Which resulted in less airflow.

 

Hang on a few moments here. The reason that the HP specs for these cars vary is simple, GM didn't list HP specs with any kind of consistency. I have a stack of documentation for 1991 since thats what I've been interested in, in that information I have at least 4 different HP numbers for the 1991 L98. Everything from 230hp, to 245hp. Also lets take a look at the facts.

The L98 auto platform and drivetrain is identical Camaro or Firebird. The only difference is the aircleaner ducting. From 85-87 the Firebird got stiffed, the aircleaner assembly was crap. Correct me if I'm wrong but 88-89 got improved ducts. These ducts are good enough that SLP uses them with their MAF cold air induction setups. 90-92 got an even better air ducting. At its smallest point the 90-92 Firebird ducting is 3" sq. Now lets look back to the Camaro... it also necks down in places to 3"... And it picks up and carries its air in close proximity to the radiator. So is there any reason why the Firebird would be 5hp less than the Camaro? Sure there is, its called marketing. Take any 90-92 Camaro, and the same year Firebird, both with an L98 and similar options to a drag strip, they'll run the same times (on average). Buyers of the Camaro are more geared towards performance, Firebird owners want a touch of class with thier performance. So GM stuck 5hp onto the sales material for the Camaro...

So lets be realistic, do the hp figures mean anything? no. Is there a correct hp figure to be found? Maybe, but how can you ever prove which is right? Do all stock factory cars setup identically run exactly the same? No... Mass produced cars aren't blueprinted. You could take two identical cars and they could run very differently. The only real accurate way to determine a specific cars true Hp is to put the car on a dyno. I'm just going to take a wild guess and say GM didn't dyno every single Fbody before it left the factory, then average the numbers...

 

I am apt to go with marketing as the source for all this confusion. GM has a rich history of putting Chevrolet first in the pecking order - especially when performance marketing is the issue. Glad the fourth gens brought along with them an end to this b.s.

There may be slight variations in the intake parts but it is my understanding that major differences would have to be in place before you would see minor differnences in hp. The reason is, and I believe most would agree, that the plenum to the heads area is the major restriction and minor variations ahead of this don't contribute to relieving the restriction in this area.

 

I don't think there is any point to getting more than a rough estimate of the Hp ratings... once you drive a car off the lot it starts to lose Hp... you've probably lost 5-10 depending on upkeep after 100k. In fact the Hp ratings are never consistent across the board when you buy a car.

Just $.02

 

I agree with everyone that actual outcome can vary and it is not a big deal. I just was trying to see if anyone could shed some light why there are so many different claims per setup. I am just surprised that for each year a certain setup does not have just one simple number. If some years there are differnces between the divisions then that can explain some of the mess up. Must be something special about the third gens that the other generations did not have.