: Northstar swap into a 1987 Fiero GT - engines and differences

01-29-14, 01:08 PM
My son and I recently purchased a Northstar for the above engine swap. Need to ID the model year.

Tag on right side valve cover is: T1DL204727. It is my understanding that the last six characters are the VIN. Just need to verify the model year as we need to purchase the computer for same and upgrade it to better suit the Fiero GT/5 speed.

Thanks to all who reply.

01-29-14, 01:15 PM
Take a look at the VIN derivative that is stamped/etched on the pad casting on the right forward side of the cylinder block, at the pan/block seam ........down below the right cylinder head front corner.

Click on a thumbnail to zoom, use your browser < to back out.

01-29-14, 02:41 PM
Thanks for the prompt reply. I have been able to get a little more information from the VIN tag:

6TU203594 LD8 4K

I hope this helps.

01-29-14, 05:37 PM
Not sure of the year, but it's the sedate 275 hp engine. Different cams and calibrations from the 300 hp L37.

01-29-14, 05:59 PM
Thanks again for the reply. How can you tell it is 275 HP ???

The pictured submarine is docked here in Portland, OryGone.

01-29-14, 06:54 PM
Just decoded the engine VIN......we have a 95 and in need of a computer for the engine swap into my son's 1987 Fiero GT. Found a 1994 computer, but not sure if the two are compatible. If the two are compatible who is a good source for chip upgrades/modifications for this application???

Thanks again to all who reply.

01-29-14, 08:49 PM
I don't see why not as long as they are the same VIN. They are both OBDI

01-30-14, 08:35 AM
Depending on engine year -

LD8 - 275 hp max, 300 lb/ft torque max, 3.11:1 final drive in FWD configuration. VIN Y - 8th character of the total VIN.

L37 - 300 hp max, 295 lb/ft torque max, 3.71:1 final drive in FWD. VIN 9 as above.

Differences in engine output is mostly cams and PCM calibrations. Pre-2000 engines are hydraulic flat tappet cam follower; 2000 and later are hydraulic roller cam plus quite a few running upgrades - different engines from pre-2000.

Electrics and electronics also changed for the 2000 MY - ignition went from waste spark to Coil On Plug, among other changes.


I'll merge your ECM compatibility question into your other Northstar-into-Fiero thread so the advice is all in one place.

For ECM programming in your Fiero application, talk to CHRfab or Wester's Garage in Canada. You might find other "tuners" in the CTS-V or STS-V forums. There's also a forum dedicated to early ECM tuning in the Engines or Discussions forums. try to find some of our member AJXTCMAN's work - he's a Cadillac Tech who has done Fiero/Northstar work.

Google "cadillac forums northstar engine fiero" or something close, always preceded by "cadillac forums .......".

01-30-14, 01:36 PM
Submariner409: Thanks for all your help. I have researched some of the Fiero forums and have found a couple of the conversions we will be doing in the future. Even managed to find one application where the Northstar was turbo'ed and then placed in the Fiero GT. Needless to say a handful of car. Too bad John DeLorean did not see his vision of the Fiero thru to that point. It would have given the Corvette owners fits.

USS Blueback (SS-561), non nuclear attack type, I believe is the submarine docked here at OMSI. Took a tour of it years ago when it first docked here at OMSI. Was an impressive tour.

01-30-14, 03:22 PM
USS Blueback (SS-561), non nuclear attack type, I believe is the submarine docked here at OMSI. Took a tour of it years ago when it first docked here at OMSI. Was an impressive tour.

There were 3 of those high speed diesel fast attacks - BARBEL, BLUEBACK & BONEFISH - they were the test beds for development of the nuclear powered SKIPJACK class (6 boats). I served in SKIPJACK (SSN585) from 06/62 through 07/64 - she was then "The fastest submarine in the world" - official statement was "In excess of 40 knots submerged". 1 knot = 1.15 statute miles per hour. Read the book "Blind Man's Bluff". Been there, done that.

Started out in '59 in the sister boat to PAMPANITO - check out this site and learn how to take the virtual tour - most impressive. http://www.maritime.org/tour/index.php


The pictured submarine is docked here in Portland, OryGone.

Not that one - your boat is a BARBEL class diesel fast attack. My avatar is of a nuclear fast attack completing an emergency surface from over 1/3 mile down.

01-31-14, 12:37 AM
Got to watch a couple of the attack guys a couple of summers ago up in the Hood Canal on simulated torpedo runs. Was a pretty cool event.