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March 23, 20188 yr

Hello all,

I am new to this forum. I have a 1977 Pontiac GP LJ model with T tops. It has the 400 in it. Been going through it and making it truly my own. The interior is in pretty good shape for 40+ years. I'm getting ready to pull the engine out and build it. Plan on painting it this Fall. Cant wait to get her all done. I found out that I have a notorious 557 block under the hood. After much research and thought, I'm going to put my block in storage and use a block that is known to be stronger, (pretty much any block dating pre 1976). I have a friend that had an earlier 400 block. He offered to let me have it. it has a 988 # on it. So I'm going to see if this block will be ok for my build. It set for a long time. We took it apart last night and it appears ok, but had water in a couple of cylinders. We shall see.

Does anyone know what make/model headers fit my setup? I will have Aluminum D port heads on engine. I'm figuring out that the headers can be tricky for proper fit.

Appreciate any and all advice. This is my 77........

Gregg

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Frosty

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Location: Davison, Michigan
Name: Da Snowman
Gender: Male
Year: 1972
Car: Lemans
Trim: Sport
Engine: 455
Style: Convertible
Color: Lucerne Blue w/ White

4 Vehicles

March 23, 20188 yr

1977GPX, welcome to FP and the madness! Nice looking GP. Of course we'd love to see more pictures.

While I have no experience with a '77 Grand Prix specifically, most guys I know usually go with one of three brands of headers for the traditional Pontiac A/G bodies. They are Hooker, Hedman, and Doug's. I think there are a few other brands out there, but these are the most common and most likely to fit. You can order these either thru Jeg's or Summit Racing, or directly from the companies themselves. Also, catalog companies like National Parts Depot, Original Parts Group, YearOne that carry G-body parts should also carry headers.

I am not clear what you mean by a 988 # on the block. Where is that on the block? Can you take pictures of all the numbers on the block and post them? That will help immensely.

Ringo64

Founders

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Location: Naples, FL
Name: Jim
Gender: Male
Year: 2006
Car: G6
Trim: GT
Engine: 3.5L LX9
Style: Coupe
Color: Black

2 Vehicles

March 23, 20188 yr

Founders

Love the GP! Look forward to seeing you and that GP around!

Last Indian

Members

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Location: Northeast Ohio
Name: Gary
Gender: Male
Year: 2000
Car: Grand Prix
Trim: GT/F1
Engine: 3800
Style: Sedan
Color: Dark Navy Blue effect

1 Vehicle

March 23, 20188 yr

4 hours ago, 1977GPX said:

Hello all,

I am new to this forum. I have a 1977 Pontiac GP LJ model with T tops. It has the 400 in it. Been going through it and making it truly my own. The interior is in pretty good shape for 40+ years. I'm getting ready to pull the engine out and build it. Plan on painting it this Fall. Cant wait to get her all done. I found out that I have a notorious 557 block under the hood. After much research and thought, I'm going to put my block in storage and use a block that is known to be stronger, (pretty much any block dating pre 1976). I have a friend that had an earlier 400 block. He offered to let me have it. it has a 988 # on it. So I'm going to see if this block will be ok for my build. It set for a long time. We took it apart last night and it appears ok, but had water in a couple of cylinders. We shall see.

Does anyone know what make/model headers fit my setup? I will have Aluminum D port heads on engine. I'm figuring out that the headers can be tricky for proper fit.

Appreciate any and all advice. This is my 77........

Gregg

3 hours ago, Frosty said:

1977GPX, welcome to FP and the madness! Nice looking GP. Of course we'd love to see more pictures.

While I have no experience with a '77 Grand Prix specifically, most guys I know usually go with one of three brands of headers for the traditional Pontiac A/G bodies. They are Hooker, Hedman, and Doug's. I think there are a few other brands out there, but these are the most common and most likely to fit. You can order these either thru Jeg's or Summit Racing, or directly from the companies themselves. Also, catalog companies like National Parts Depot, Original Parts Group, YearOne that carry G-body parts should also carry headers.

I am not clear what you mean by a 988 # on the block. Where is that on the block? Can you take pictures of all the numbers on the block and post them? That will help immensely.

Welcome 1977GPX! The 988 most likely has xx in front of the whole pn# which is 481988 which was the resurrected 400 block from 1971-1974 (much stronger block) the block was resurrected in 1978 and part of 1979 for the 6.6 Firebird. So they gave it the casting number xx481988.