That is going to be one heck of a project. I assume you are looking for the nostalgia impact of the vette FI system. Is the old ramjet system totally shot??? if not that setup is worth some serious bucks.
I imagine you will need to fabricate fuel rails and drill injector bosses into the manifold. You would need to retrofit a throttle body on top of the manifold, or at the very least somehow fit the ramjet throttle blade with a throttle position sensor. Edelbrock sells a TBI to EFI conversion kit for Chevy trucks that you could remove from the supplied manifold and adapt to the ramjet manifold.
Since that project will be an enoumous undertaking and will require serious fabrication skills perhaps you could consider another method. The new GM ramjet 350 is similar in appearence to the old 57 system you have. and supposedly this ramjet system found in the GMPP crate motor is or will be available as a stand alone system from either GMPP or possibly Arizona speed and marine
The beauty of that system is it was developed as a stand alone marine system, the computer module actually is mounted in the intake somewhere, just need to hook up the 12v power and set up a FI fuel system.
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Frank W
90 5.0 LX coupe Stone stock soon to be daily driver
74 Chevy Laguna Type S-3 305 apart in garage, getting a 454 to put next to it
www.chevellepages.com/folingo