New to the forum 1978 1/2 ton 350 swap [Archive]

Charlieatthedisco

08-22-2013, 11:56

Hello all, have been doing some research lately and I have many questions regarding a 350 swap to a 6.2 diesel. First off can it be done with a 1/2 ton 1978 silverado c10? the engine currently is dead so my switch to diesel is mostly for smog purposes (California truck) as well as MPG. I should also mention that this truck has sentimental value it was my grandfathers which is why I am going to deem this as a project. Other questions are, where should I be looking for parts? and I have found a few rebuilt 6.2's on ebay and the local Craigslist here. I just want to know how much trouble I am really going to run into. I know I will need a different TQ (but which one?) a new wire harness and possibly another battery. Will the suspension be able to handle a heavier engine? and what type of radiator would I need?

Robyn

08-24-2013, 06:22

Hello

Welcome to TDP :D

What you are wanting to do is pretty easy.

The engine will physically drop in and bolt up.

Now there are some differences too.

TRANSMISION

If the truck has a stick shift you will need the clutch, pressure plate, flywheel from the 6.2, and probably the throw out bearing too.

Auto tranny is somewhat easier.

If the rig has a TH400 tranny your pretty close.

If the rig has a TH350 then use a TH 400 converter.

The 6.2 must have a 6.2 or 6.5 flex plate.
These engines are externally balanced and the flex plates from other engines will not work.

The governor in the rear of the tranny must be swapped out for a diesel version (easy job, 20 minutes)

The lower flywheel cover from the 350 will need to be replaced with one from a 6.2, no matter which tranny.

using an auto tranny, either 350 or 4oo will require a vacuum control valve on the RH side of the IP to run the vac modulator.

EXHAUST

Best to have a dual system on these. (build to suit)

ELECTRICAL

The alternator wiring will cross right over likely.

Use the hot line to the ign to power the injection pump.
Or you can use the ign wire to run a relay and then the IP

RADIATOR/COOLING

Scare up the largest GM unit that will fit.

Likely a mid 80's 6.2 truck radiator will fit the 78 fine using the factory hold downs and rubber cradles.

Use the factory radiator hoses too.

Use a 6.2 fan and clutch assembly.

Be sure to fit the stock fan shroud from a 6.2 truck.

FUEL SYSTEM

Drain the stock tank and your good.

The 6.2 had a mechanical fuel pump just like the 350

Be sure to add a good diesel fuel filter assembly

Racor makes some nice ones.

Or you could use a factory unit if you can scare one up.

I would use a Racor myself

Go with either a 2 micron or a 5 micron filter.

You must have a fuel return line from the injector return rail and the IP back to the tank.
Normally this is a common 1/4 inch tube, and the 78 should have a line already there that will work.

The 6.2 engines will have a return line that connects the injectors as well as the IP to a common point up front at the top of the engine.

GLOW PLUGS

You will need to fashion a control to run the glow plugs.

To keep it simple, use a Ford starter relay mounted to the inner fender well on the LH side.

Install a push button in the dash to operate the solenoid.

Install 60G glow plugs (these wont burn out easily if you glow too long)

Add a second battery tray (factory stuff is around that will fit.
Tie both + together, ground both to the engine and the chassis.

12V system just like the 350 , run power off the RH battery to the starter.

Use existing wires at the starter, they will work fine.

SUSPENSION

Whats there should be ok

Well, this will get you started.

Pretty much an all GM parts swap.

I probably forgot something, but these are the basics.

Keep us posted, pix are always welcome.

There are many wonderful folks here that will chime in as time goes by.

Keep us in the loop, have fun.

Ohhhhh, be careful about ebay engines.
If you can see it in person AND hear it run, FAR BETTER

Missy