Pontiac 400 in a Grand Prix 2+2, just a few questions...

[86GP2+2]

I have a 1986 Grand Prix 2+2 that I bought last summer to swap in a Pontiac 400 stroker motor I built a couple years ago. I am getting ready to start the swap and was curious if anyone who had done this could help with what kind of headers will work and if the standard Pontiac V8 motor mounts will bolt to the k-member. Thanks in advance.

 

[drogg1]

I believe some gbodys came with 301s and so there are frame side motor mounts for Pontiac V8s. I am not sure about headers but member Bonnewagon should be able to give you more information if you message him.

 

[pontiacgp]

1979 you could order a Grand Prix or Grand Am with a 301 and a 4 speed stick...

 

[Bonnewagon]

A Pontiac 400 will slip right in BUT you must use the 301 mounts. The rubber clamshells that bolt to the frame are easy to get but the perches that bolt to the block are not so easy to find. You want the '78 to '81 265/301 LeMans/Grand Prix perches. Ebay is a good source, Craigslist, etc. Firebird or other model block perches will physically fit but will raise the motor a few inches. What year is the block? The blocks with the five or three bolt holes in each side are the easiest to use. Earlier two hole blocks you will need an adapter available from the big vendors. I once bought the perches at a real parts store. But since they are not a "wear" item, they don't make them anymore.

 

[86GP2+2]

A Pontiac 400 will slip right in BUT you must use the 301 mounts. The rubber clamshells that bolt to the frame are easy to get but the perches that bolt to the block are not so easy to find. You want the '78 to '81 265/301 LeMans/Grand Prix perches. Ebay is a good source, Craigslist, etc. Firebird or other model block perches will physically fit but will raise the motor a few inches. What year is the block? The blocks with the five or three bolt holes in each side are the easiest to use. Earlier two hole blocks you will need an adapter available from the big vendors. I once bought the perches at a real parts store. But since they are not a "wear" item, they don't make them anymore.

I had this motor in a 1980 Firebird and I have perches. The block is a 1972 or 1973 casting. The mounts are the same as the ones rockauto shows. I'll have to check on the perches for a grand am or grand prix though, because I want the hood to fit and it did not fit on the firebird. The block has the three hole style setup.

 

[G-Body_Vet]

Fwiw, if you happened to get a set of perches from a big body car it will significantly raise the engine. I may stand corrected, but I thought the f-body and g-body perches are slightly different as well. The last headers I knew of for a g-body with a poncho mill were made by Maddog Headers. http://maddogheaders.net/products/pontiac
I settled for RA IV manifolds and I'm happy with the fitment.

 

[86GP2+2]

Fwiw, if you happened to get a set of perches from a big body car it will significantly raise the engine. I may stand corrected, but I thought the f-body and g-body perches are slightly different as well. The last headers I knew of for a g-body with a poncho mill were made by Maddog Headers. http://maddogheaders.net/products/pontiac
I settled for RA IV manifolds and I'm happy with the fitment.

I'm hoping the mount perches I have are the shorter ones. As far as headers go, I'm going to try the Firebird ones I already have first. I thought about the RAIV manifolds, but I have D port 6x-8 heads on it right now. The headers at Maddog are $1050.00, that's very expensive. I've already got a MSD Atomic sitting in my living room to install, gotta keep costs down.

 

[G-Body_Vet]

I have the d-port RA manifolds, not the round port RA IV. Haven't spoke Pontiac in awhile! I got them from R.A.R.E. and they weren't exactly cheap either.

 

[86GP2+2]

I have the d-port RA manifolds, not the round port RA IV. Haven't spoke Pontiac in awhile!

Nice, I thought they were only for round port! Where did you get them?

 

[tdvick]

Mad dog headers aren't $1050. They are $525 or $550 a pair. I have them. My car is still apart so I can't comment on fit, but they look very nice.