454 OBS

Vehicle Type:

1990 Chevrolet OBS



Clay’s OBS is a 1990 454ss truck with an original 25k miles on it.  When the truck came to us it has already been swapped with a dry sump LS9 and a 4L80E transmission.  Clay bought the truck mainly for its sum of parts and great, low mile, condition body.  Once in our hands we drove the truck, inspected what we had to work with, then came up and a build plan with Clay.  Knowing that the engine was already great, we decided to keep the engine, but just clean it up a bit.  The transmission however worked well but we came up with something a little more fun.  We pulled the truck down the bare chassis, had it blasted, and went to work putting it on our chassis table.  The engine was set into a better location with a new set of engine mounts and then we mounted a 2012 BMW dual clutch transmission behind it.  Our transmission was from a v8 M3 and had very low miles.  However, with the power we planned on making, we replaced the clutches in it for a set that would hold the extra power.  This transmission is an electronically (paddle) shifted 7 speed manual transmission with a gear ratio split from 4.35:1 in first and a final 7th gear of 1:1 ratio.

Once up on the table with the drivetrain in place, we designed an inner stiffening member in software and had it water jetted for us.  Before installing, we cut boxing plates and welded them in to create a stronger frame.  The new stiffener also provides a location for the transmission crossmember as well as a front pivot point for the torque arm rear suspension.  Yes, that’s correct..  With the help of Cortex Racing, we incorporated their torque arm as well as a watt’s link to keep the rear end centered.  While at it, we had GearFX build us a custom 9″ rear end housing and supply us with a nodular iron third member.  Another trick part of the driveline is a new old stock Nascar 2.75:1 gear set that GearFX found for us, REM polished, then assembled with an Eaton Trutrack LSD.  

For the front suspension we purchased simple and effective control arm package from QA1.  The arm is not only stronger but allows the use of a coilover and provides a raised coilover mounting location.  The upper mount relocates the upper arm as well to give more caster angle and increase camber gain under compression.  To give this truck the best ride quality and rebound control we installed a set of JRI single adjustable coilover shocks with remote reservoirs.