Crank to Flywheel =
Crank to Flywheel = 24" long
Widest Point = 22" wide
Oil pan to highest point on S/C = 26" Tall
TF-904 = 16" long
Tail housing = 6.5" long
D300 = 12" long
Unneeded Brackets on
As stated above the L67 uses an Eaton generation 3
M90 blower with a 3.8" diameter pulley. Horsepower gains are seen by
replacing the blower pulley with a smaller unit, this increase
maximum boost and shortens the time it takes for the supercharger to
produce boost by spinning the blower faster than stock. Several
places sell pulleys that extend all the way down to 2.5" in
diameter. Realistically unless you are running race gas you
need to be a little conservative with your choice in pulley
diameter. From what I have read a 3.4" diameter pulley is a good
starting point along with some sort of air filter upgrade and cooler
This is the part I hate. I can wire stuff
but I am not fast and it is frustrating. This time I had
Performance modify my stock wiring harness so I only had to hook
up a few wires (6 wires). He labeled everything and included a
nice 4 panel fuse box to run the PCM. Jim also re-programmed
my PCM to eliminate the missing security, transmission and emission
related code. I did find quite a few places that could handle
the PCM re-programming but the few that I contacted asked me what
codes I wanted eliminated. Being as I had never used this
motor before I had no idea what needed to be eliminated. Jim's
Performance has done the programming for a few rockcrawling
competitors so he knows what needs to be eliminated so the motor
will work in a rock buggy.
From what I have read the stock plug wires and
coil packs are not a weak link on this motor and have a reputation
as being more reliable than aftermarket parts on this motor.
Make sure the alternator is working good at WOT.
Mine appeared fine showing 12-13 volts in most situations but at wide open
throttle (WOT) the voltage would sag to 10v or less causing the engine to
You should not need a VSS (I am not running one) if you are
running a "dumb" manual shift automatic transmission or manual. You'll need
to keep the first oxygen sensor but the second one can be faked with a
Do not use teflon tape on any of the sensors that screw into
the block (especially the knock sensors). A lot of the sensors ground thru
One last thing on the wiring, this motor seems pretty picky
about it's grounding. I had lingering hesitation issues for over a year
and finally got rid of them by running a ground wire from the battery negative
terminal to every grounding point on the motor and chassis.
There are two options, run the stock stuff or
headers. The L67 has a cast iron exhaust manifold on the
drivers side (or front of the original FWD car) and a tubular
exhaust manifold on the passenger side. There is a crossover pipe
that runs along the back side of the motor that dumps the drivers
side exhaust gasses into the passenger side manifold. From
there the exhaust heads to a large collector complete with a large
spring loaded misalignment joint. I used some 2.5" header
bends to start the exhaust routing from there.
Performance wise I have heard a set of headers in
a dual exhaust configuration will easily gain you 30hp but also
requires enough room to route the exhaust pipes on both sides of the
buggy. Most of the guys I know running dual exhaust and custom
headers with this motor have rear engine cars. For a front
engine car I think the stock setup makes for very easy exhaust
routing since everything dumps to one side. For performance gains
with the stock exhaust routing you can get stock headers for roughly
$700 or get nearly the same benefit with ported stock exhaust
manifolds for almost a fourth the price.
Upon further research I discovered
ZZ Performance makes a "power log" which replaces the cast iron
exhaust manifold on the drivers side (front) with a tubular version.
The benefits to this exhaust manifold are a 5lbs weight
savings and the elimination a huge flow bottleneck by increasing the
ID of the collector tube by 30% over the stock manifold. The
passenger side (rear) manifold doesn't have this restriction. The
power log is a bolt in piece and runs only $119 with no core charge.
A ported passenger side (rear) manifold runs an extra $95 + core.
Another bottleneck lies in the stock flex coupler that bolts up to the passenger
side exhaust manifold, all of the exhaust gasses merge here at the flange which
has a 3" ID. The problem lies in the fact that the flex joint (shown on
the right) chokes the exhaust path down to a 2.125" ID. On the left you
can see I welded a 3" ID tube to the flange which will eliminate the bottleneck.
The 3 inch tube fit really well after I ran a 3" hole saw thru the flange to
clean up the bore.
If you do want to make custom headers I found
header flanges for sale at West Coast Fiero.
Camaro V6 headers (Pacesetter shown) fit perfectly. I
simply ditched the supplied crossover pipe and have a cheap set of block hugger
headers for half the price of a set of FWD headers.
Passenger side view.
Drivers side view.
The location of the intake is the reason you won't
see this motor become a common swap. As seen above the intake is to
the rear of the motor which would put it right into the firewall of
a standard vehicle or the dash of a custom tube vehicle.
The above cobra head intake hose was the best way
to minimize cab intrusion of the intake hose. I found the
above head at
www.intakehoses.com. Utilizing this adapter puts the rear
most point of the intake hose 12" behind the bell housing mounting
I made a small hole in the cobra head adapter to
mount the intake air sensor.
If you like finding exotic parts there is an
intake that bolts to the M90 blower from an Australia Holden
Commodore that points the intake tube towards the front of the
Pictures can be seen here.
Here is a list of some of the engine performance
upgrades I have stumbled across that would pertain to use in a
Aluminum Roller Rockers - good for up to 25hp gain.
Aluminum means less rotating mass.
Roller rocker install write-up.
Electric Water Pump - Frees up about 7hp. -
Oil Volume Kit - Increases the engine oil pressure.
Ported Throttle Body - TB ported from 69mm to 72mm. there
is also a
new billet 78mm TB in the works.
Aluminum Heads - Lighter weight and re-designed ports and
Ported Stock Heads -
Nitrous Kits - 55, 65 and 75hp shots.
Supercharger Pulleys -
You'll want to plug this in order to keep it from sucking oil into
the engine when off camber towards the passenger side of the car.
The picture above shows the PCV valve home in the top of the
Supercharger housing and you can see the hole that leads into the
intake. This hole needs to be plugged. I chose to just fill my
PCV valve with some oil resistant RTV, then I re-installed the PCV
Now I needed a new vent for the valve cover so I
drilled and tapped the oil fill cap for a 3/8" NPT fitting with a
1/2" hose barb on it. Shown is a 45" fitting but as it turns
out I need a 90 degree fitting to clear the coolant hose that runs
above the filler cap. Basically I'll run the 1/2" line over, down,
under and back up the side of the motor to create a plumbers trap,
then cap the hose off with a small air filter.
There are several different oil filter mounts that
came on the different cars this engine is found in,
West Coast Fiero has some shown here. I mention this
because you may run inter interference issues between the oil filter
and front upper links since the oil filter sticks out in font of the
engine off to the passenger side. I have also heard an oil filter
from a 4.3L Chevy (Found in S-10 trucks, blazers and Chevy Astro
vans) has the same diameter and thread but is 1" longer (for more
Power Steering Pump
The L67 motor uses a Saginaw CB style pump.
This pump is a dead ringer for the TC style pumps except for one
less mounting ear and a larger output shaft. I opted to send
my pump off to PSC to have it modified for more flow and pressure.
I went with a 26 x 19 dual pass aluminum radiator
Ron Davis. The radiator has Ford style outlets which puts
both on the drivers side. I also had Ron Davis install a fan
shroud and dual fans. The fans are controlled by my PCM (via a
relay), Jim at Jim's Performance setup the first fan to come on at
150 deg and the second one at 180 degrees. I have never seen the
water temperature go above 180 degrees with this setup.
I also had to make a custom thermostat housing to
get the upper radiator hose pointing away from the firewall and
towards the radiator. The tubing shown above is1.5" diameter from a
180 degree header bend.
The radiator was connected to the motor with a
stainless steel hose kit I picked up off of E-bay. You can get
these kits form Summit Racing as well. I used a 48" kit which came
with enough hose, clamps and adapters to plumb both intake and
return lines. For reference the radiator ports were both 1.75"
diameter, the motor intake port was 1.5" diameter and the motor
return was 1.375" dia.
The L67 has a 60 degree GM bell housing pattern.
A 700r4 from an S-10 that had a 2.8l V6 will bolt right up to it as
well as a TF 904/999 from a 4WD that had the same 2.8l motor
(Cherokee's came with a 904 for a short while, 84-86 I believe).
The nice thing about going the 904/999 route is you can get the tail
housing from a CJ that had a D300, shorten the tail shaft on the
904, attach the tail housing and then bolt up a D300 with no
adapters required. I have also seen a powerglide attached to this
motor on some competition rigs, I suspect an adapter was used.
I saw a post on a message forum that mentioned an
adapter that would convert the 60 degree pattern to a regular 90
degree pattern. I never confirmed this.
Edit 11-1-07 While looking thru some classifieds I found a reference
to a TH350 adapter plate, sure enough it is sold by Speedway
notched for the L67 starter
With the TF 904/999 transmissions the bell housing
must be notched on the drivers side to utilize the engines
starter. I also added a tie plate to reinforce the bellhousing
where it was notched.
The one thing I am not clear on is the torque
converter (TC). I had thought my setup originally had a
Cherokee TC but later I discovered the Cherokee TC pilot was too
large to engage into the L67. I don't think the original L67 TC was
used because the flex plate on my motor was re-drilled for a new
hole pattern and .25" spacers were used to space the TC away from
the flex plate. Since I originally bought my
motor/transmission/transfer case combo as a unit it is possible that
the previous owner had a custom converter built. If I learn
more on this topic I will update.
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