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Old 07-22-2000, 07:20 AM
Mike87 Mike87 is offline
Join Date: May 30, 2000
Location: Low Country
Posts: 110

Yes you can have your intake modified for multi-port fuel injection. You'll have to do a search, but I do remember a long time ago coming across a company which does this including AMC V8s (even had a picture).

Second you will need a throttle body that will mount to a 4bbl flange. Make sure whatever you find has an idle air control.

Next comes the fuel rail. I have no idea what the center to center bores are between GM and AMC, but perhaps the company that modifies the intake will be able to help you there.

Next is the computer and wire harness. Do you use the stock GM or an aftermarket such as Accel? With the stock you will be stuck with the factory calibration. This causes two problems.

1) You can't re-adjust the computer for whatever power differences between your AMC and the Chevy V8 at WOT. (You can sort of - see explaination)

At part throttle you are in closed-loop mode. The O2 sensor (don't forget you need to add that also) will adjust your fuel to stoich air/fuel ratio of 14.7:1.
Under heavy throttle, you'll want about 12:1 for max power, cat protection, and piston protection. This air/fuel ratio is out of the range that the O2 sensor can control. There are O2 sensors which read a wider range, however they are very expensive and you will need an aftermarket computer that is compatible with it.

Warning, those air/fuel ratio gages you'll find in catalogs like Summit or Jegs use a standard O2 sensor and therefore can only tell you when you are above or below 14.7:1. But they cannot tell you by how much, so be very careful! When you are not at stoich, they are not accurate (even if they have a scale on them!!)

You can cheat your way around the WOT problem provided you're making less than 20% greater power than the original engine that you got the computer from. Use an adjustable pressure regulator and increase pressure to add fuel.

2) If it's a GM computer, it won't be compatible with the Ford Duraspark system. I'm not sure, but a lack of signal from the distibutor may cause the system to go into limp-home mode which means you'll be open loop. Therefore, you may have to switch to an HEI which will cost you a few bucks, but if you look on this website someone listed in a forum that there is a place that makes a conversion for AMCs.

Finally, you will need new lines. A carb system uses 6 psi, a TBI about 15-22 psi, and MPI about 40-60 psi. You will need all new lines for high-pressure injection and a high flow pump. Plus you will need a return line back to the tank.

Good luck. If you decide to do this, let us know how everything comes out.

[This message has been edited by Mike87 (edited July 22, 2000).]
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