I'd say don't do it either. The no-torque 4.6 is going to have trouble in that large a vehicle. Curb weight on the Cyclone has to be close to the Crown Vic ... and a stock Crown Vic certainly doesn't generate much excitement in the acceleration department, especially compared to a 429 CJ.
Anyway, Western Motorsports in Calgary, Alberta, Canada is a dealer for SDS EFI systems. They have a specific stand-alone 4.6 / 5.4 modular engine kit.
Check out:
http://www.wmsracing.com/wmsweb/sds.htm
cheers
Ed N.
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