1987 Fiero GT 3800sc swap with an engine from a 1998 Grand Prix GTP (Page 1/2)
VROOMZ28 MAR 06, 12:31 AM
I purchased a 1987 Pontiac Fiero GT with 63,699 miles this past November (2019) and have been restoring and upgrading the car. I will be swapping the 2.8L for a supercharged 3.8L engine from a 1998 Pontiac Grand Prix GTP. I’ll try to do my best to document by restomod and engine swap as I go through. I have been inspired and informed by the others who have don the swap and have offered they build lists, and experiences. I have found The posts. And YouTube videos by “Lostbutnotforgotten” and “AustinH” extremely helpful in my planning and preparation.

My engine build is going to consist of a 1998 L67 3.8L supercharged engine from a Pontiac Grand Prix. I’m going to add the following items /modifications to increase power:

Gen V M90 supercharger and intake manifold from a 2004-2008 Grand Prix GTP L32 engine
ZZP Stage 2.5 Intercooler
ZZP XP (hot cam) performance camshaft
CompCam 136lb conical valve springs
Cylinder Head porting and polishing
ZZP Power logs exhaust manifolds
Smaller supercharger pulley
And a few other items I will detail as continue on..

The car has almost no rust, but the paint has clear coat separation and no clear coat at all on the top surfaces. The interior is in good shape for a 32 years old car, and the car is compete with all the original parts and no damage history. The car has only had a few owners, and stayed here locally all its life. The major issue with the 87 GT, was it wasn’t running when I purchased it. It had been sitting for at least two years. Two owners ago, the car developed a “rod knock” and stopped being driven. The car engine was worked on with the oil pan removed and the connecting rod nuts taken off. This owner lost some of the parts and gave up on trying to fix the car, and sold the car.

The next owner, bought all the parts that were missing, but didn’t have the time or energy to fix the poor Fiero. It sat in a carport for almost two years, where I ended up buying the car. I was able to put in a new battery, put the engine back together, and get the thing started. I was just checking to see if the starter would crank and possibly get the engine to turn over, and was shocked when it started right up! The car had been sitting for years, and in less than week, I was able to get the car started. The engine didn’t sound the best, but it idled good and would move under it’s own power. Pretty good for a little effort and time.



Here are some pictures of the car when I first saw it.





You can see the video of me bringing the Fiero home and my wife’s reaction here:

https://youtu.be/1Oz8a4xM7Ag?si=7KMU4eh5Y5fryl67

[This message has been edited by VROOMZ28 (edited 10-02-2023).]

cam-a-lot MAR 06, 06:14 AM
Good luck with the build, and welcome to the Forum!

[This message has been edited by cam-a-lot (edited 03-06-2020).]

VROOMZ28 MAY 05, 12:00 AM
First step... deep cleaning years of dirt and grime





VROOMZ28 MAY 05, 12:13 AM
Next, replace and upgrade the rusty, nasty, seized up braking system, and drain, refill, and bleed the lines.

The back brakes are going to be replaced with drilled and slotted rotors, but I will be using remanufactured stock 1987 calipers.

For the front brakes, I am replacing the hubs, rotors, and calipers using the vented brake upgrade kit from the Fiero store:

https://www.fierostore.com/...px?s=56004&d=379&p=1













VROOMZ28 DEC 31, 02:34 AM
https://youtu.be/1Oz8a4xM7Ag


Buying my 1987 Pontiac Fiero GT

[This message has been edited by VROOMZ28 (edited 12-31-2020).]

VROOMZ28 SEP 29, 02:36 PM
The 3800sc Donor Car! (January 11th 2020)

Once I had the brakes working, It was time to start swapping the engine. I found a one owner, 1998 Grand Prix GTP that had 190,000km (118k miles), in Macon, Georgia. The owner bought the Grand Prix new in 1998 in Canada and drove it down to Georgia. The car had been in amazing condition, had all maintenance records kept, oils changed regularly, and looked in almost new condition when his 17 year old son was hit in the front (from the side) by a F150 that missed a turn. The car was totaled, but the engine was very usable, except for a broken front cylinder head.







I bought the crashed car for $800 and loaded it up on a trailer… I drove it the 2.5 hours home to Alabama and took it home. The next day I took the donor car to a rented storage building where I was going to cut the crashed front away from the engine, and pull the entire front cradle (subframe) with the engine, transmission, harness, computer, and driveshafts. Having everything I could off the car ended up being a huge blessing later on since I had axles to make custom driveshafts with, and the harness and computer to modify and transplant into my Fiero.









[This message has been edited by VROOMZ28 (edited 09-30-2023).]

VROOMZ28 SEP 29, 02:58 PM
Pulling the 1998 L67 3800sc Engine (January 17th, 2020)

Once I had the engine, transmission, Engine harness, computer, axles, spare nuts, bolts, screws, and all the other stuff I wanted from the donor car, I put it up for sale. The interior was in great shape, and I was able to sale the body, interior and rest of the care for $200. So the engine for the swap ended up only costing $600, plus the expenses for storing and trailering the car home.



I brought the Engine, Trans, and other stuff to my home garage.



I was going to do a partial rebuild of the engine and began to disassemble it down to the short-block. It was a good running engine so I wasn’t going to mess with the block, pistons, crankshaft, or any of the bearings. I found someone on FaceBook that had a set of 3800sc heads sitting in his garage that I’d be able to use to replace the cracked head.









I cleaned up the engine block and gathered up all the parts I was going to use to rebuild and modify the 240hp 1998 3800sc L67 3.8L Supercharged engine. I purchased an Eaton M90 Gen V supercharger that would give me 20 addition horspower. I bought ARP studs, stainless steel valve springs, LS4 Lifter, and a ZZP XP Cam.

[This message has been edited by VROOMZ28 (edited 09-30-2023).]

jelly2m8 SEP 30, 04:15 AM
This swap has been well documented on here, there's all the info you need on here.

Your are doing this right, the 3800's are finicky with rebuilding, unless you do not have to get into the bearings and pistons, do NOT take the short block apart. google 3800 Rebuilds, the VAST majority of failures are ones that were rebuild.
Patrick SEP 30, 04:30 AM

quote
Originally posted by VROOMZ28:

The car was totaled, but the engine was very usable, except for a broken front cylinder head.




I had no idea that a head (other than the driver's or passenger's!) could be damaged in an accident... but yeah, that head is definitely cracked!
VROOMZ28 SEP 30, 08:28 AM
Rebuilding the Supercharged 3.8L L67 Engine (January-May 2020)

From January thru May 2020, I disassembled the engine to the small-block, and cleaned it up, acquired some good (but dirty) 3800sc heads from Larry Curchoe, and sent them off to my local machine shop (Piltcher Automotive), went on a shopping spree at ZZP, RockAuto, Summit, JEGS, Amazon, Ebay Motors, Intense Performance and a few other places. This was where I went a bit overboard, and went with my dream build for the 3800sc.


My Mechanic, Logan

My 1987 Fiero GT will get the following upgrades:

1998 Grand Prix GTP 3.8L Supercharged Engine
3800sc Series II
Engine was from a one owner donor vehicle
Partial engine rebuild
Painted with Eastwood’s 2K urethane ceramic engine paint
Upgraded to an Eaton M90 Gen V supercharger
ZZP Stage 2.5 Intercooler
3.4” Supercharger Pulley
Cadillac Northstar Throttle-body Swap and ZZP Adapter
ZZP (CompCam) XP high performance camshaft
Modified heads with 136lb valve springs, ARP Studs
LS7 Hydraulic Lifter
ZZP Stainless Steel Valves
Jet-Hot ceramic coated ZZP PowerLogs (front and rear)
Jet-Hot coated crossover tube with DEI Titanium exhaust wrap
Flowmaster 3” high flow catalytic converter
Custom 3” stainless steel exhaust to muffler
FlowTech Afterburner Muffler 5036FLT (3” inlet 2 x 2.5” outlets)
Dual 2.5” stainless steel exhaust to C6 dual tips


1987 Fiero GT Engine Upgrades

1998 Grand Prix GTP 3.8L Supercharged Engine
3800sc Series II
Engine was from a one owner donor vehicle
Partial engine rebuild
Painted with Eastwood’s 2K urethane ceramic engine paint ( https://amzn.to/3r2zc69 )
Upgraded to an Eaton M90 Gen V supercharger
ZZP Stage 2.5 Intercooler
3.4” Supercharger Pulley
Cadillac Northstar Throttle-body Swap and ZZP Adapter
ZZP (CompCam) XP high performance camshaft
Modified heads with 136lb valve springs, ARP Studs
LS7 Hydraulic Lifter
ZZP Stainless Steel Valves
Jet-Hot ceramic coated ZZP PowerLogs (front and rear)
Jet-Hot coated crossover tube with DEI Titanium exhaust wrap
Flowmaster 3” high flow catalytic converter
Custom 3” stainless steel exhaust to muffler
FlowTech Afterburner Muffler 5036FLT (3” inlet 2 x 2.5” outlets)
Dual 2.5” stainless steel exhaust to C6 dual tips


New and improved high-flow water pump


Champion 3-core Radiator


ZZP 3800sc “Power Logs” stainless steel exhaust manifolds, sent off to JetHott for ceramic coating.


ZZP XP Cam, CompCam LS7 Lifters, CompCam 90# Valve Springs, Rollmaster Double Roller Timing Chain


Eaton M90 Gen V Supercharger that has improvements and adds 20hp vs the Gen III M90


New lower intake manifold for the Gen V M90 Supercharger


replacement 3800sc cylinder heads after coming back from the machine shop (Piltcher Automotive) and getting the new ZZP stainless steel valves.


Cylinder Heads from the machine shop with CompCam 90# Valve Springs and new seals/retainers


redone heads mounted on the engine with the oil pump, water pump, and parts going back on the engine. Its a great feeling when you start putting stuff back on and making the engine look new again.

[This message has been edited by VROOMZ28 (edited 09-30-2023).]