86 firebird engine swap from v6 to 73 sbc 400 and th350

Asked by GuruR2R23 Feb 15, 2020 at 12:41 AM about the 1986 Pontiac Firebird

Question type: Car Customization

thinking of buying 86 firebird and want to put my 73 400 sbc and th 350 in it. I
will scrap the computer. The motor and trans are currently in an 82 grand prix
and wondered what, if anything, will interchange, and what I should replace or
modify to fit this drive train.

5 Answers


This sounds like a question for a Pontiac performance forum, where they can go into specifics (hard to do that here). As to fitment, people swap in big blocks into 2nd and 3rd gen Firebirds all the time, so more than doable. Obviously motor/tranny mounts and front suspension will need to be upgraded for the V8 and drive shaft will likely need replaced, and you will probably want a beefier rear end in there.

smog is not an issue and it is a small block not a big block. I know about the radiator and the motor and tranny mounts and the power steering pump as i put this setup in an 82 grand prix and had to shorten the drive shaft. But wondered about wiring and anything else that might need done.


I only meant it as people swap in big blocks into these cars, so if those fit then so will your 400.

ok next question is can i use the parts i used to put this powertrain in a gbody to mount in the fbody. or will i have to get different mounts. also is the speedo electric or mechanical

Your Answer:


Looking for a Used Firebird in your area?

CarGurus has 370 nationwide Firebird listings starting at $5,950.


Own this car?

Share your experience with others.

1986 Pontiac Firebird

Review another car

CarGurus Experts

  • #1
    Samuel Moore
  • #2
  • #3
    Paul Martin
View All

Know more, shop wisely


Related Models For Sale

Used Chevrolet Camaro
590 Great Deals out of 9,394 listings starting at $2,000
Used Chevrolet Corvette
670 Great Deals out of 12,002 listings starting at $3,200
Used Ford Mustang
921 Great Deals out of 22,940 listings starting at $1,995
Used Ford F-150
5,896 Great Deals out of 126,911 listings starting at $1,995
Used Dodge Charger
694 Great Deals out of 30,219 listings starting at $2,895
Used Pontiac Grand Prix
3 Great Deals out of 192 listings starting at $1,500
Used Porsche 911
349 Great Deals out of 3,819 listings starting at $16,500
Used Chevrolet Monte Carlo
4 Great Deals out of 191 listings starting at $3,999
Used Chevrolet Impala
254 Great Deals out of 3,905 listings starting at $950

Used Cars for Sale

2002 Pontiac Firebird For Sale
7 Great Deals out of 62 listings starting at $7,950
2001 Pontiac Firebird For Sale
16 listings starting at $6,600
2000 Pontiac Firebird For Sale
3 Great Deals out of 31 listings starting at $12,326
1999 Pontiac Firebird For Sale
27 listings starting at $9,988
1998 Pontiac Firebird For Sale
16 listings starting at $5,950

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.