1983 6.2 liter Diesel to 5.7 liter SB Conversion
I decided to write this all down since there have been such a variety of answers to the many questions I’ve had during this conversion project. I started out with a 1983 K20 “4X4” Chevy Silverado with the 6.2 liter “J”code diesel engine and TH400 automatic transmission. The engine in the truck was badly damaged, and I already had most of the components for the 350 engine in my garage so this is the reasoning behind the swap if you were wondering WHY go gas? I didn’t have the funds for a replacement used diesel, nor a newer complete roller Vortec motor, which would be the route I wanted to go with this. The used 5.7-liter Vortec motors I was finding in my area, were in the 500-700 dollar range and would still require a complete rebuild, seeing is they all had around 200,000 miles on them OUCH!. So I’m utilizing what I have!
OK, the 350ci engine I have is an older 2-piece rear main, 4 bolt. I also purchased a serpentine belt system, as well as a used set of “906” Vortec heads off of a 1996 Chevy truck for $300. There were many articles floating around out there about the hardened valve seats on certain 906 heads restricting flow. However, the newer information and testing has proved the opposite to be true. So if you can get a set of either, grab em’! My plan is to bore the cylinders .030” over and rebuild it, as well as use the stock crank and connecting rods “rebuilt of course”. I’m using a set of Keith Black 142-030 dish pistons, and a cylinder head improvement kit from Competition Products part #8511. I plan on running an HEI distributor, a Howards Cam and lifter kit part #CL112011-11 with an Edelbrock Performer intake manifold part# 2116, and a Quadrajet carburetor. This should provide me with good fuel economy, along with the power when I need it. As well as the option to do modifications later without needing a new bigger carb!
The serpentine system I purchased includes all the necessary brackets, the newer style A/C compressor “HT-6” that will be replacing the A-6 “Monster” Compressor that was in the truck originally, as well as the newer style alternator “CS130D”. However, I needed the pigtails/plugs for both the alternator and A/C. The A/C clutch plug is AC Delco PT209 and rear of the A/C is part# AC Delco PT1798. The Alternator is a 4 pin connector part # AC Delco PT368. All the connectors are readily available and can be found at: http://www.repairconnector.com/brands/JMC.html
As far as the wiring goes, on the A/C Clutch, the wires are not polarity sensitive. Which means you just hook one to ground, and the other to your positive source. On the rear of the compressor, this is the high-pressure cutout switch, and you can either run the hot wire or the ground through it. It automatically cuts the compressor off, if the pressure hits 427psi. With the alternator wiring, like I said there’s 4 pins. Pin A, is not used, Pin B needs a 12volt switched source, Pin C Not used, and Pin D 12 volt always hot. You can see the diagram at: http://paceperformance.com/p-3980-se...nnections.html
as well as numerous other places on the web.
The power steering pump was another issue to contend with. Since the truck used a hydraulic brake booster, I needed to keep the original pump that was in the truck but still be able to use the newer serpentine belt and brackets, not the V belt it’s setup for. It turns out these pumps are interchangeable and you can swap the pulley over as well as the needed brackets for proper mounting to the serpentine brackets and motor.
A couple snags I’ve run into that I really couldn’t find mentioned, I’m running an aluminum timing cover, and a stock harmonic balancer. Finding the correct timing pointer has been a quest, but I ended up going with a Summit Part # 163800 as the cheap ones wouldn’t work for two reasons. One they wouldn’t bolt up to the aluminum cover made by RPC, however similar to the Summit G6300W. Two, being that it was to long and would cover over the entire balancer. The Summit #163800 pointer would require a slight shave to make it the correct distance from the block and I shortened the screws as well. Another snag I hit was the water pump. I purchased a reverse rotation, high volume pump off our favorite auction site “NOT”. However, these 97 serpentine systems use a different style pump that has a wider bolt pattern and a threaded stud that connects to the fan clutch. So I went with the pump for a 97 Chevy truck. The next issue was the 97-water pump, does not have the bypass port that is on the Gen 1 350 block, passenger side. I had to tap and plug this port on the block, and use the bypass system that was built into the Edelbrock 2116 intake manifold. The instructions for the 2116 manifold are quite vague on this “bypass” subject, however if you look up part number Edelbrock 7116 on Summit.com it explains it in detail. So the engine build has gone straight forward, and with these few snags, everything has gone smoothly. In between building the motor and waiting on parts, I completely removed the interior and pretty much everything off the outside as well. Time for paint! I sanded everything down, fixed a few of the small rust holes that were behind the rear wheel wells, a couple dents hear and there. I painted the engine compartment and while I was there, I decided to remove the engine wire harness, and add a couple wires I needed for the electric choke, tachometer, oil pressure, and temp gauge, as I’m installing some real gauges. Not just the ones that came with the truck. I’m using an electric fuel pump as well, Summit Part# ATXE8012S, and I will be using the pink wire that was used for the injection pump on the original harness. The fuel pump is a lower pressure unit as I’m using a newly rebuilt Quadrajet carburetor and according to the instructions, they recommended only 5 PSI max to this carb. Because of this I also purchased a fuel pressure regulator and fluid filled gauge to go with it. I’m going to be utilizing the large canister style fuel filter unit that was used on the diesel setup as well since I still had a new filter for it. Overkill, yea. But why not? I’ll let you guys no more as I get closer to firing it up. Should be there eventually.