L31 5.7L Vortec - CSFI conversion to MPFI

[In-Tech]

The external injectors are the key so you don't have to rely on the "spider". I'll help what I can :)

[Fast355]

The external injectors are the key so you don't have to rely on the "spider". I'll help what I can :)

That they are! I am really enjoying the dual plane setup. I cleaned up the ports in the dual plane and opened the runners up to match the port opening of my 210cc aluminum heads. Swapped to a 1200 cfm 4bbl dry throttle body and a 4" air intake setup with a 100mm MAF housing. My 11:1 383 runs so well with that dual plane. Engine modeling software is showing about 540 ft/lbs of torque at 4,000 rpm and 530 hp @ 5,700. With a 5.13 rear gear and a 2,800 rpm high STR converter in the 4L85E its fun to drive despite being wrapped up in a 3+ ton van.

Ignore the carb sitting on top. Only used it for spacing to get the overall height ballparked for fitment. I ended up with a 1" open center nitrous plate as a spacer between the throttle body and manifold. Have yet to hook it up but I bet that 383 is a monster on a 100 shot.

[In-Tech]

HaHa, yepper, 100hp shot, yuck... start out at a 175hp shot :D

[In-Tech]

I can't find my drawings and strobe pics from the early 1990's. A 3 bar plate works so much better to atomize the fuel. Think top bar with normal degree exit of nitrous in a V and twin fuel bars exiting fuel so nitrous blows thru the fuel at a 90 and stratisfies in an upward pattern. Everyone to this day still puddles fuel in the center of the manifold.