Ian,
You will be hard pressed to get the same fuel economy out of a modified iron6 vs a stock 4200.
The 2 hardest parts of installing the 4200 are:
- bulding the engine & trans mounts
- changing the fuel pump/tank/lines over to efi, but I think the aftermarket now makes a bolt in EFI tank for the 1st gen. The line etc. if you do them in braided line is not to hard to do. Hard line under the car without a hoist is painful.
Other than getting a 2wd 4200/4l60e with wiring harness and gas pedal/harness stub. You have to change the oil pan to rear sump, modify or buy one. The electrical is hook up like 6 wires. Jeremy can convert the harness and reprogram the PCM so its painless to install.
The exhaust runs on the passenger side. You will need to shorten your dive shaft about 1"
These are the big items the rest is hoses for various fluids. Time consuming but not hard.
Talk to Al in Delta and Frank in Summerland - take a day and go see them - Frank just completed a 4200 install into a '53 chevy PU. Your not pioneering a path here its been done and support is avilable.
