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

Asked by 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

83,815

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...

35

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.

Your Answer

Add photo

Related Questions

Search Pontiac Firebird Questions

Pontiac Firebird Experts

#1 Samuel Moore
Samuel Moore
Reputation 910
#2 dandyoun
dandyoun
Reputation 760
#3 Justin Hatfield
Justin Hatfield
Reputation 730
View All

Related Models For Sale

Used Chevrolet Camaro
631 Great Deals out of 39,687 listings starting at $2,995
Used Ford Mustang
719 Great Deals out of 39,136 listings starting at $1,000
Used Chevrolet Corvette
369 Great Deals out of 20,435 listings starting at $3,688
Used Dodge Challenger
430 Great Deals out of 25,754 listings starting at $7,980
Used Dodge Charger
546 Great Deals out of 29,486 listings starting at $2,343
Used Pontiac Grand Prix
31 Great Deals out of 3,796 listings starting at $1,195
Used Chevrolet Monte Carlo
17 Great Deals out of 1,734 listings starting at $1,695
Used Chevrolet Impala
998 Great Deals out of 36,811 listings starting at $1,800
Used Ford F-150
3,492 Great Deals out of 207,570 listings starting at $1,273
Used Chrysler 300
527 Great Deals out of 21,438 listings starting at $1,500

Used Cars For Sale

2002 Pontiac Firebird For Sale
6 Great Deals out of 132 listings starting at $6,495
2001 Pontiac Firebird For Sale
77 listings starting at $7,599
2000 Pontiac Firebird For Sale
3 Great Deals out of 92 listings starting at $3,800
1999 Pontiac Firebird For Sale
58 listings starting at $4,990
1998 Pontiac Firebird For Sale
49 listings starting at $4,999