Aftermarket spider-to-MPFI manifold for Vortec heads
Thread asks if enough of us would buy a bolt-on conversion package.
The core idea
Original post is looking for a Vortec SCFI to MPFI package with the intake, rails, injectors, external FPR, and a CSFI-to-8-injector harness all wrapped up so it bolts right onto the factory heads and keeps the stock TB/EVAP/EGR plumbing.
Claim is it lets us swap bigger injectors, service one at a time, and kill the dripping poppets and junked regulators that plague the stock CSFI setup.
Kit contents and wiring
The pitch includes a manifold with ports for external injectors, matching fuel rails, and a plug-and-play harness that either keeps the CSFI connector or leaves you to splice into the stock loom.
They figure it could use existing SBC MPFI injector hardware, so the rails are standard LT1/TPI stuff you can pull from the boneyard and the stock ECU already knows the peak-and-hold or saturated injectors.
Cost talk
Price guess was $400–$600 if someone like Edelbrock handles the tooling and production run.
Another reply pushes the math higher: injectors $300, harness $200, intake $200, low-volume rail $200, plus R&D overhead, so expect to toss an extra $500 on top from Edelbrock.
OP counters that a manifold is closer to $200, injectors $300, rails $75 retail, and that R&D spread over 20 units only adds about $25 each, so a junkyard parts route could be $250–$350.
Why people want it
A bunch of guys say they’re in as long as it stays simple and plug-and-play.
Nobody wants to spend time fabricating a marine setup.
One even says he’d pay $1,100 to skip the marine intake headaches and just bolt on a finished solution.
Demand for a dedicated marine version is described as near zero, so everyone wants a street/EFI-friendly build instead.
Alternatives mentioned
Someone suggested just an adapter harness feeding a ready-made manifold and a simple adapter plate for the throttle body.
Holley pricing for the TB, rails, gaskets, and manifold adds up to about $1,300 without injectors or wiring.
Others link to that GMPP Vortec TBI manifold converted to MPFI with EGR, purge, MAP sensor, and point out it was done cleanly by Hot Rod Solutions, implying a similar kit could be copied if a manufacturer stepped up.
Community sentiment
Overall there’s clear interest in a packaged solution, with enough people willing to pay for convenience that the thread is trying to prove to Edelbrock or another builder that the demand is real, even if it means being patient while the tooling gets sorted.