What changes do i need to make when replacing a 301 with a 400 in my 79 Firebird?

Asked by Derrek Sep 07, 2015 at 09:57 PM about the 1979 Pontiac Firebird

Question type: Car Customization

I was told the 400 came out of a 75-76
Bonneville. It has 2bbl. carb & intake. I
wanna change to 4bbl. & keep my TA
hood & shaker on my bird. Please
help!!

2 Answers
188,365

Paul answered 8 years ago

Besides some wiring modifications, new motor mounts and maybe heavy front springs, new exhaust there not much more that I can think of for the change over, good luck with her...

1 people found this helpful.
Mark helpful
135

1WikdWagon answered 8 years ago

Actually from first hand experience this should be a basic bolt in swap. Almost nothing from the 301 will interchange with the 400 though. Will have to locate an intake from a 350, 400, 428 or 455. 326 may be the same also but not positive. Edlebrock performer is an option over stick that will work with the shaker. Depending where you are I have three extra stock intakes. Including a good 68 intake. The 301 mounts should also work with no real issue as long as you have a post 70 block. Will have either 5 or three bolt holes for the mounts on the block. If it only has two bolt holes it's pre 70 and you are gonna have issues with mounts. Speaking from experience with that also.

1 people found this helpful.
Mark helpful

Your Answer:

Related Questions

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
15 Great Deals out of 467 listings starting at $10,995
Used Chevrolet Corvette
26 Great Deals out of 769 listings starting at $15,900
Used Ford Mustang
36 Great Deals out of 1,623 listings starting at $8,995
Used Dodge Challenger
31 Great Deals out of 772 listings starting at $12,979
Used Dodge Charger
30 Great Deals out of 897 listings starting at $4,888
Used Pontiac Grand Prix
3 listings
Used Porsche 911
18 Great Deals out of 238 listings starting at $22,980
Used Chevrolet Monte Carlo
5 listings starting at $9,800
Used Ford F-150
311 Great Deals out of 13,802 listings starting at $4,500
Used Chevrolet Impala
6 Great Deals out of 133 listings starting at $3,495

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.