Pontiac 455 in a G-body

[G-Body_Vet]

Ok, I'm not crystal clear on this particular swap. Could someone chime in on what's entailed?

1. Do all 301 mounts work or only the g-body ones? Asking because I've heard the Firebird ones will work as well.
2. Is there a particular year of blocks that drop in with the 301 mounts? I've heard only certain years will work due to a different number of mount bosses in the casting.
3. Is there heater box interference?
4. What manifolds or headers will fit without trouble?

 

[G-Body_Vet]

No Poncho 455 owners?

 

[Bonnewagon]

ALL Pontiac V-8's are the same dimensions except for the 265/301. I had a 400 in a Malibu and it fit with no trouble at all. The 78' to 81' A/G body 301 block perches are the ones you want. I never tried the F body ones but the older A body perches are taller. The frame mounts are the same I believe. Useing the 301 A body ones are the way to go. Look for the 5 mounting holes on the side of the block, those with 2 holes won't work without adapters which are available and not hard to fabricate. Headers are allmost impossible to find but either Hooker or Heddman made them, I don't know if they still do. Stock log manifolds fit and the RamAir cast iron headers for 2nd gen F cars will work too. AC fits but makes getting at the pass side plugs a b*tch unless you go in through the wheel well .

 

[G-Body_Vet]

ALL Pontiac V-8's are the same dimensions except for the 265/301. I had a 400 in a Malibu and it fit with no trouble at all. The 78' to 81' A/G body 301 block perches are the ones you want. I never tried the F body ones but the older A body perches are taller. The frame mounts are the same I believe. Useing the 301 A body ones are the way to go. Look for the 5 mounting holes on the side of the block, those with 2 holes won't work without adapters which are available and not hard to fabricate. Headers are allmost impossible to find but either Hooker or Heddman made them, I don't know if they still do. Stock log manifolds fit and the RamAir cast iron headers for 2nd gen F cars will work too. AC fits but makes getting at the pass side plugs a b*tch unless you go in through the wheel well .

Thanks for the response. That's what I wanted to know.

 

[bigdan]

interesting project ....

a pontiac engine in a g body grand prix ....and a 455 !

did a similar swap years ago but in a big grand prix 77 ....

indeed a 455 im a small ,lighter g bodied grand prix is nice !

rare too!

go for it !

 

[deanlemans81]

Hey Steve, just an add-on to what`s already there, you will also need a trans with a bop bolt pattern. Use a 301 a-g body wiring engine wiring harness if you can find one because elctrical accessories are not all in the same place as the 3.8v6. Using most of a 301 accessory drive makes also makes things easier. You need a 71 and up block to get the revised engine mount bolt holes that will fit with the 301 a-g body block brackets.

It`s not a difficult swap but goes better if you can get a complete 302 a-g body donor carcass for all the little crap any engine swap needs.
dean

 

[G-Body_Vet]

I should be good with the wiring since the car has a 305 in it right now. The hard part is going to be finding 301 parts. I read somewhere that "Shotgun" is the resident Pontiac guru so I sent him a PM about some mounts for a 301.

As for the trans, I'm just going to go with a 200-4r with a universal case. I also found dual bolt pattern flywheels for 400/455's too that can be used with the metric trans. I know I'll have to have it built to hold up to the torques but that's fine. Thats another why I've been hunting for a 373 rear end too.

I had a '80 Regal with a 400 some years ago but I didn't do the installation. I could roast the tires at will with highway gears.
It should be fun now that I have the time and funds to build it the way I want.

 

[Bonnewagon]

Not much of the 301 brackets and pulleys will fit a regular Pontiac V-8. It's best to get all that stuff with the motor if possible.

 

[19cutlass79]

Not much of the 301 brackets and pulleys will fit a regular Pontiac V-8. It's best to get all that stuff with the motor if possible.

Yup I got lucky with my wagon the previous owner had already did the pontiac 350 swap told me himself the hardest part of the whole thing was tracking down the brackets and pulley's.

wade

 

[G-Body_Vet]

Yup I got lucky with my wagon the previous owner had already did the pontiac 350 swap told me himself the hardest part of the whole thing was tracking down the brackets and pulley's.

wade

I'm not having any luck in my search. I need to locate some junkyards with older stuff.