Well gee... Where to start

When I started my research on teh 3.4L TDC, I owned a 1991 Pontiac Grand Prix, production #74 of


? I was the 2nd owner of the car. The previous owner ordered it in early 1990 before it was available and had it built to suit and deliverd in early 1991. He was/is a cheif steward at Portland International Raceway and wanted the car for track activities.
After receiveing the car from the local Pontiac Dealership, Weston Pontiac in Gresham, he had the Cams reground and the timing redone. Retarded the exhaust cams. From what I've found, only about 10 degrees.
I purched the car from him in late 1993 and drove it until New Year's Eve 1999 when I got hit by a drunk driver who promptly ran after the collision. He T-boned me in the Driver's door and broke the left front wheel before swinging around a 2nd time and slamming the car in the rear driver's wheel and side swiped the entire length of the driver's side before bolting. I got his plates and he was picked up about an hour later. In all, my GTP was totalled and I was shaken, not stirred.
Out of disaster comes hope!!! I had my 1988 Fiero GT that I was preparing for a 355 transplant (someday) and had always loved the pull of the 3.4L TDC in my GTP which is nearly 2000 lbs heavier. Ripped my head off in that car, why not in the Fiero

So that was the beginning. I bought the totalled GTP back from salvage for $1000. Pulled the motor, tranny, ECU, axles and everything else I thought I might ever need. Including the GTP badges

Then I sold the car BACK to salvage for $500. Not a bad deal I think.
The motor sat for over a year while I got my life together. New Home, 1st child, you know. Finally, I got started on the swap.
I wanted to get alot done while I was at it so from 1993 until I started the swap, I spent hours on the phone and Internet researching what mods were available for this motor. Found some leads and uncovered some of the history of the motor and of my motor specifically. Discoverd folks that had access to actualy GM documentation concerning the HP output of the first 100 motors and stats. Amazing stuff.
I had the timed and custom Cams, so my list began to grow from there. When the motor was out, I put that list into action.
1-Bored the TB, ported and polished
2-Hone Strued port and polish upper and lower intake manifolds
3-Port matched the Exhaust, Custom super high flow exhaust with NO cat (or mufflers really

)
4-Decked the head to improve compression to 10.5-1
5-3 angle valve grind. 5 was available but at a low end loss
6-New pistons, rings, seals etc. Forged cranks and rods.
7-Modded ECU
8-Fuel Pressure Riser and Regulator
9-Underdrive and lightweight aluminum pulleys
10-Custom PS pulley application
11-High torque starter
12-Custom Axles
13-284 Getrag 5-speed tranny (Grand Prix GTP tranny)
14-Auxillary oil cooler
15-Auxillary tranny cooler
When all that was done, the motor went into the Fiero and runs super fast and strong. It's loud as hell and I've been pulled over for doing 65 in a 40 (in 2nd gear no less) and excessive noise. The cop was impressed with the motor and car and let me go

I'm getting ready to tear it down again and probably will in the next few weeks. I'll be adding copper o-rings instead of head gaskets and reworking the heads/pistons to reduce the compression back to 9.5:1 for a Turbo application. That will be a hyrid T-3/T-4 turbo running only 7 - 11 lbs of boost at first with 28 lbs possible. At a full 28 lbs, I'll be putting out over 550 HP and I don't know if the tranny will handle it.
That is really the weak spot in all this... the tranny. Even the added strength of the 284 is getting close to stressed out with 300+ HP and I certainly don't think the 282 will handle the 450 HP I'm planning on running.
So, I'm going to have my tranny rebuilt as well and reinforced if possible.
I know very little about the 3.5L motors as they did not exhist when I started this project. What I do know is that they are essentially a Northstar with the back two cyls lopped off. The engine management system runs the same. Beyond that, I have no clue.
Yes, I prefer the 3.4L TDC over the 3.5 because I have always loved it. Because of the power. Because of the sound. Because of the speed.
I have no speed limiter on my car and the rev limiter is set at 7400. Pulls forever and sounds incredible. Can't beat it.
I've got a huge step-by-step diary for the motor build up I'll have to find. It was alot of fun and certainly isn't over yet.
I've rambled, I know. But I hope that's a good start for you. Perhaps I can help get you hooked up with some shops that can do some of these mods for you.
Let me know what else I can help with!
DKOV -