BUILD THREAD Grand Prix LS/Th400

[Cams85GP]

I’m redoing this post in the appropriate “build thread” section.

This is my first “build thread/engine swap” so I’ll try and organize it best I can.
Picked up a Gen 3 4.8 back in October. And after stripping it down, .030 over, and all new internals(except rods and crank) I’ve finally got it in!

Start:
3.8/Th200

 

[Cams85GP]

Gen 3 4.8 .030 over
I’m going carbed for a few reasons,
Mainly because I like the look of a carb/air cleaner, and I eventually would love to do a blow through turbo set up, which I think looks badass. But for now this is the set up:


Sloppy stage 1 cam
PAC 1218 springs
BTR trunnion upgrade
BTR chromoly pushrods
LS7 lifters
Holley dual plane intake
Ofcourse new valves,gaskets,timing chain,etc etc

 

[Cams85GP]

originally was going to paint it the old Pontiac metallic blue, but made a last minute decision to go with the “burnt” copper colour, which I think looks good against the aluminum.
After cleaning the engine bay of grease, dirt,and oil spray, it turned out pretty good.

Also Picked up the TH400 for the shop, rebuilt with a shift kit. 2400 stall converter

 

[Cams85GP]

Got the Carter fuel pump mounted and plumbed. HotRod fuel hose braided line and fittings.
Also got my EBay headers installed, and started throwing alt/ power steering stuff back on, as well as coils. Eventually I’d like to get nice looking brackets but these will do for now. Also I don’t think I need that big of an alternator.

 

[Tony1968]

Looking good 👍 Getting close to start up.

 

[Cams85GP]

Couple updated engine pics..
Changed alt/power steering setup,
added 750 QFT,
Champion Rad
couple vacuum lines, fuel line etc
Various other things.
I ran the fuel line in from the back to try and clean up the engine bay a little, since I wasn’t planning on using a fuel pressure gauge.
This is my first swap, so If anyone sees anything that’s not right or could be better, please feel free to say something.

Thanks.

 

[Tony1968]

Looking great 👍

 

[GR8ONE68]

Looks great! I will be in the market for a G Body Grand Prix in the next couple of years. I am now putting together a plan. As I move forward I would like to pick your brain on installing an LS in the Grand Prix. So far, my plan is:
1986 or 1987 Grand Prix
LS3 Vette motor, modifications TBD
4L80e Transmission, I want overdrive
I'll use the Holley controls for the motor and trans
12 Bolt Posi, gears TBD
I will paint the LS Pontiac Blue Metallic, I'm an old Pontiac guy through and through. I had a '68 GTO for 25 years. I had the original numbers matching motor that I rebuilt for it and then I pulled it out for a 455 that I built for it. I liked to take it to the track from time to time and if I broke something, I didn't want it to be an original part. I also put in a race prepped 200-4R and a 12 Bolt Saf-T-Trac out of a '71 Grand Prix, it was a direct bolt in. There is no way I would swap an LS into an old Pontiac like that, but since the G Body is already a corporate motor, I see it as fair game. The first new car I ever bought was a 1983 Pontiac Grand Prix LJ Brougham. It had the Buick 3.8 V6 in it.

 

[Cams85GP]

Well I realized I haven’t updated this thread in a long time, so I figured I’d get to it.
Got the car fired up back in July, on the first crank. I couldn’t believe it, it sounded bad *ss with just open headers. No leaks, great oil pressure.

Had a shop in town do up a true dual exhaust, couple Jegs 2 chamber mufflers, exit behind rear tires GN style. Very happy with the sound, great idle, drone isn’t terrible in town.

Installed the new gauges in place of the factory dummy lights. I tried to make it look as factory as I could, mounting them was actually pretty straight forward. Added the tach to the column for now. I might eventually put one where the clock is, but I just think having a 5” clock front and centre is hilarious, so I’m keeping it for now.

Also got the electric fan hooked up along with the Derale controller. I do have a shroud I’ll be putting on, but this seems to be working fine for now.

Ive been playing around with timing tables on the MSD, I have it in a decent custom setting now. So far I’ve put a couple hundred KMs on it and it’s working pretty good.

The next projects will be some new suspension parts, upgrade the brakes, and upgrading the rear end. I might be able to get my hands on an 8.8, so that might be the route I go.

Any questions or suggestions please feel free to message.