Swap to 6.5L or not?

[LKellyHarley]

I am in the process of rebuilding and restoring a 1984 Chevy C30 3+3 Dually. The truck started life with the 6.2L. The previous own swapped to a 454. The motor is very strong and starts every time. It has a few issues (carb, ignition, etc.). Overall it's a good motor. My initial thoughts have been swap to an LS6.0 with modern tech, etc. The LS engines are becoming easier and easier to swap everyday. After doing some research I'm now interested in swapping to a 6.5L. First the appeal of having a diesel and next the shear ease of mounting and tranny boltup. Although this body style never came from GM with the 6.5, the 6.2 and 6.5 are dimensionally the same as with the 454.

I'm sure someone here has already done this many times. But my specific quesiton I couldn't find. I'm more interested in the pros and cons of both the LS and 6.5. What can I expect from the 6.5 in cost to swap, maintinence, ease of rebuilding if needed, at least cost of refreshing the moter. The LS is extremely versital and are capable of producing gobs of power. That's not what I'm after, but it's possible.

My main focus of the restoration will be driveabiltiy without costing a fortune to operate. I also wouldn't mind being albe to tow upwards of 16-20k lbs. if needed.

[Robyn]

Easy swap

The 6.2 and 6.5 are for all intents and purposes are identical.

The difference is the cyl bore.
The actual block and heads are again almost identical, and most stuff swaps between them.

A 6.5 will bolt right up to the Turbo 400 (likely whats there) if it has a 4 speed manual, still no worries.

The flex plate or flywheel and clutch must be for the 6.5 though.

6.5 is an externally balanced engine and the flex plate from a 454 will not work.

Go with a mechanical injection though.

The electronic injection is far nastier than you need to deal with.

Pretty basic refit to get the 6.5 in there.

All bolts right up

Scare up an engine with the complete serp drive belt/accessory drive as this makes life very good.

the engine mounts are all the same location as before.

Wiring will all be fine too.

They likely used the pump hot lead for the distributor.
Everything else is no issue.

The radiator is likely the HD that it had.

Good luck

Missy

[trbankii]

One thing not mentioned is whether you want the turbo on the 6.5L or not. Stuffing the turbo in there could be a fitment issue.

Comparing the 6.5L to the LS6 is another matter. Depending on who you talk to, horsepower and torque numbers would look something like the following:


6.5L - 155 hp / 340 lb·ft
6.5LTD - 215 hp / 440 lb·ft
LS6 - 385 hp / 385 lbf·ft and up…

Or are you talking about the LQ4/LQ9 Vortec 6000 truck engine?


6.0L Vortec - 300~345 hp / 360~380 lbf·ft and up…

As far as ease of swap, if you go the route Robyn advises with the mechanical injection 6.5L has the advantage of not needing all the computer control swapped in as well. The later electronic injection 6.5L engines are going to take more work to swap the computer stuff over as well - and I’m guessing there is less aftermarket stuff out there than you’re likely finding with the LS6 swap.

My neighbor has a 5.7L Vortec Suburban. While cruising around, he gets no better than 13mpg whereas I can usually get in the low twenties in comparison. Towing, I’m still usually in the upper teens while he’s down into single digits. Diesel has been running a premium, though, so you’d have to figure the mileage benefits of the diesel. Chances are that you’d be able to find everything you needed for the 6.5L swap significantly cheaper than an LS6 would run you.

[Robyn]

OOOOPS

THE TURBO, AHHHH YESSSS

Scare up a used Banks setup for the 6.2 and your set.
There were also other mfs that made a 6.2 retro fit turbo system for these engines.

The Banks and other systems places the turbo waaaaaaaaaay far forward on the RH front and the down pipe does not run into the AC box.

The factory 6.5 system off the GMT400 trucks can be made to work, but AC BOX MODS ARE REQUIRED.



I have seen a factory 6.5 turbo manifold adapted with a set forward spacer under the turbo to get it far enough forward to allow the down pipe to clear the AC box.


Banks would be my choice.

Zero issues, bolts right on and there is no waste gate to fool witth.

Good luck

Missy