Is the 73 310hp SD455 a myth?

Asked by GuruMLXFV May 19, 2020 at 05:21 PM about the 1973 Pontiac Firebird Trans-Am

Question type: General

This is not a question, but a correction. There is a common myth the 73 SD455 was rated at 310hp. It was originally designed to, but it was NOT! Both the 73 and 74 SD455's had 290hp. Due to government regulations, no 310hp SD455 was ever sold to the public and was reduced to 290hp before the 1st one in 73 was ever sold. Fact. Rest assured, I  always thought the same thing until I did some research.

2 Answers

F_O_R answered 3 years ago

I think the 310hp engines were pre production engines that did not meet smog requirements.

2 people found this helpful.
Mark helpful
155,245

james answered 3 years ago

Beginning with the 1972 models advertised horsepower is SAE net. 1971 and older models are SAE gross. The difference is net horsepower is measured with the engine in the vehicle, accessories installed and operating, and the horsepower reading is taken at the drive wheels. Gross horsepower is measured at the flywheel with the engine not installed in a vehicle. Hope that helps! Jim

Mark helpful

Your Answer:

Related Questions

Firebird

Looking for a Used Firebird in your area?

CarGurus has 20 nationwide Firebird listings and the tools to find you a great deal.

Postal Code:

Shortcuts

Search Pontiac Firebird Questions

CarGurus Experts

  • #1
    Samuel Moore
    Reputation
    1,590
  • #2
    taver91
    Reputation
    1,320
  • #3
    Paul Martin
    Reputation
    1,270
View All

Find great deals from top-rated dealers

Search

Related Models For Sale

Used Chevrolet Camaro
19 Great Deals out of 469 listings starting at $11,999
Used Chevrolet Corvette
23 Great Deals out of 767 listings starting at $18,999
Used Ford Mustang
35 Great Deals out of 1,585 listings starting at $5,977
Used Pontiac GTO
4 listings
Used Dodge Challenger
30 Great Deals out of 759 listings starting at $11,480
Used Dodge Charger
41 Great Deals out of 852 listings starting at $4,888
Used Pontiac Grand Prix
2 listings
Used Porsche 911
18 Great Deals out of 250 listings starting at $22,980

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use. Content will be removed if CarGurus becomes aware that it violates our policies.