I had been holding off on
finalizing the motor position in part because I was not sure what to
do about the exhaust. The stock exhaust manifolds I was using
had been modified for more flow and the original plan was to re-use
them. Two thing got me thinking otherwise, one being the dump
on the passenger side where the two sides merge ended up being right
in the middle of the chassis frame rail and two the driver side
manifold was cracked. What I really wanted the first time around was
a set of headers but the Grand Prix headers are ridiculously
expensive to the tune of 6-800 dollars and would still dump in the
same location. Custom headers were another option but I was
quoted $800+ from several places which was a little rich for my
I then remembered a thread on
Pirate 4x4 where someone mentioned the Camaro 3.8L V6 having the
same flanges as the FWD 3.8L I was using. Unfortunately I
could not find any pictures of these bolted to my motor so I decided
to bite the bullet and order a set. The ones I picked up were
made by Pacesetter for a 95-02 3.8L Camaro. I went with the
Armor coat option which ads about $200 to the headers ($424 total)
in the hopes it would cut down on the heat in the interior.
There is a painted set available for a hair over $200 if you want to
save money and skip the coating.
One other thing, if you go the
Camaro header route be sure and pick up a set of plug wires for a 96
3.8l Camaro as well. These wires have 90 degree ends on both
teh coil and plug side and will clear the headers. The Stock
L67 wires have a straight on the plug side and there is no way to
keep a few of them off the headers.
Anyway, the headers arrived about a week
later and I crossed my fingers and did a test fit. The bolt
pattern in the flanges lined up perfectly and both sides dumped nice
and close to the block (passenger side shown above). The
header set does come with a Y pipe which runs under the oil pan an
ties both headers together, I could not use it without changing the
oilcan for a Camaro pan and my passenger side drop t-case meant the
driveshaft would collide with the Y-pipe.
Drivers side fitment.
I ended up chopping up the Y-pipe to
re-use the flange it had on the passenger side. On the driver
side may try and get the flange re-flared a bit lower down to pull
it up above the lower frame rails. Despite this the
fitment was better than I could have hoped for and I tacked in the
motor mounts for the last time.
My tube coupling finally showed up
(ordered in December) and since the motor was in position I could go
ahead and make the engine cage. While I like the locking feature a
lot of these fabricated tube coupling come with the flaw in the
design is they really only work if all the coupling on the tubing
are in mounted in the same plane. The two mounted in the
angled section of my engine cage required me to grind the front
keyed section down to be able to remove the cage from the top.
On my previous chassis I made my own couplers with flat joining
sections and never had any issues. I went with the purchased
option this time to save a week of lunchtime lathe/mill work.
Next up was mocking up the intake which
sticks out way past the engine block as seen in the first picture. I
should have the motor far enough forward in the chassis to hid the
intake in the dash (or at least that is the plan).
I added two braces that tie the center
section of the dash to the frame rails. On the drivers side
the brace hugs the transmission for maximum foot room. I did not
make it removable to the passenger side brace would have to allow
lateral movement of the transmission for servicing. The passenger
side brace also jogs around the intake.
A pair of braces from the windshield
down bars to the shock hoops rounded out the chassis additions for
this update. I spent a good part of the next week drawing up
brackets and plates to be cut at a local laser cutter (more on this
later). While I waited for those parts to get cut I decided to
jump ahead to something I have ready to go, the rear link mount
My Ballistic fabrication link mount
brackets were not quite what I wanted so I set about modifying them.
One of the golden rules of rock buggy building is to leave no
hang-up points on the underside of the chassis. I did not
realize it at the time but the bracket system hung down below the
mounting bar by nearly an inch to accommodate the larger cartridge
style joints. Since I was using smaller 7/8" rod ends I was
able to cut .50" out of the tabs and then slot the top and bottom
covers to eat up another .50" of height. The one catch was I
needed to ensure I could get the link mount bolts out, so the center
tabs were clearanced for the bolt head and positioned far enough out
so the bolt heads cleared each other when pulling them out. I
then welded the lower section together on the bench, transferred it
to the chassis, added some internal bracing before dropping the
cover onto the assembly.
I will need to re-do the lower link tabs
on the axle since the rod ends are maxxed out as is. The upper links
tie into the chassis roughly the same height as my old chassis. Once
I figure out the bracing in that area I'll double shear the mounting
bolt and final weld the bolt sleeve into the frame.
I did run my link mounting options thru
the 4 link spreadsheet and here's the theoretical numbers I came up
with. Despite the lowers being 3" higher than the old chassis
I came up with very similar numbers. For reference my old
numbers can be seen
here. The main difference is the slightly higher roll center and
anti-squat percentage. For reference I used a 42" tall tire for my
calculations, so the centerline of the axle tube is 21" and I am
aiming for 8" of up travel.
The rear seat frame was shortened in the
back to clear the upper links at full stuff.
Later in the week I added some bracing
as well as a gusset over the top of the link bolt sleeve. I
will eventually add a tab so the mounting bolt is in double shear
but am holding off till I figure out where the exhaust will run.