1984 was the last year for the Carter Thermoquad carb. In 1985, Chrysler switched to the Rochester Quadrajet for all 4bbl applications.

The following vehicles were equipped with Rochester Q-Jet carbs:

1985-1988 Dodge Trucks and B-Vans with the 360 4bbl
1985-1989 Dodge Diplomat/Plymouth Gran Fury police cars with the 318 4bbl

About 8 year ago, me and a mechanic friend did a 4bbl swap on my 1985 Dodge D150 truck. The truck had a 318 V8 with the factory 2bbl. We ripped out the 2bbl and installed a used Edelbrock Performer intake and a reman Edelbrock Performer 600 cfm carb. The Edelbrock ran OK but it had numerous issues and I wasn't happy with it.

I had a Rochester Q-Jet carb that was originally on a Dodge Truck 360 V8. I had the carb rebuilt by a local rebuilder and put it on the truck. Gas mileage, power and overall driveability went up. The truck would start instantly - cold, warm, hot.

The Q-Jet is a great carb - providing you have a good carb to begin with and it is rebuilt properly. If you a looking for a spreadbore carb, a rebuilt Q-Jet would be the way to go.

IMO, the Q-Jet is a much more reliable carb than a Thermoquad. Unfortunately, Thermoquads don't age well and can be incredibly tempermental - especially the later ones equipped on Lean Burn/Electronic Spark Control engines.