My goal was to install this engine so that it appears as close as stock as possible. I also wanted it to be as reliable as a stock setup. Before I did anything, I bought the JTR V8 conversion manual and I read it from cover to cover. I would recommend this book to anyone that is considering this conversion. It provides a significant amount of information that can save a lot of work down the road. The one thing that it does not specifically address is going from a 4.3 to a 350. It focuses mainly on converting older 2.8 trucks to a 350. I will do my best to address all issues related to this conversion that the book does not cover.
The 350 is approximately 4.5" longer than a 4.3. In order to make room for the 350, I decided to do the following:
1) Move the radiator and condenser as far forward as possible.
2) Install Flex-a-Lite dual 12" electric fans in place of the engine driven fan.
3) Move the tranny back 1".
All of these modifications should give me at least 1" clearance between the electric fans and the farthest forward pulley.
The 4.3 and 350 use the same computer. The only difference is the PROM chip that is installed in them. I am just going to plug the entire 350 computer into my 4.3 harness. The 4.3 harness also has the same connectors as the 350 harness. The Knock sensor wire needs to be relocated and lengthened but other than that, it will work fine.
The 4.3 transmission will bolt directly to a 350. I have been told many different things as to whether this tranny will hold up behind a 350 or not. I have asked dealership mechanics, local tranny shops, and posted the question on many message boards on the Internet. From what I have learned, the 92 and newer trannys are the same. The only difference is the Servo and the size of the TV valve. I am going to install a Corvette servo and TV valve which should provide for relatively firm shifts. Hopefully this will prevent the 350 from burning up my tranny. I will let you know how this works out after all is said and done.
Engine Prep
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