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Tuesday, May 15, 2018

Trailblazer SS manifold swap with LM7 5.3 truck.

GM let their engineers run and they came up with a better performing intake manifold than even the stock early truck style. I did swap this using parts of the original 2000 LM7 setup. The bare manifold is GM part # 12580420 which I got from Amazon.
TBSS on the right Early truck on the left
       The orginal fuel crossover won't fit over the TBSS manifold. I made some braze on connectors from steel hydraulic fittings. Threads turned off and bored to .500" 3/8" JIC ends interchange with -6 AN fittings
Here is the steel crossover section I cut out.
Crossover connection made with Earl's speed-seal teflon line. I made an Aluminium retainer to hold a 3 bar map sensor in.
I'm using DEKA 80lb injectors which are longer than and the original fuel rails from the truck manifold. Truck rails will work with trimming and spacers. They  need different holes drilled
Oring for the crossover is size 112. It needed changed as it had taken a set and was no longer flexible. I used a Viton Oring
Added a fuel pressure sender in place of the regulator
Installed and running. I used the truck manifold fasteners after removing the rubber washers.
 Running good enough the install and refine the tune...plenty of fuel at the moment
This is what the default Megasquirt Goldbox transmission control screen looks like.