To 6.2, or not to 6.2

[hunters628]

Okay I’ve been reading a lot, and I mean A LOT, on this topic and I am growing more conflicted and would like to weigh in on the opinions of others and get a general idea of any extras I will need to buy.

My truck is a 82 k10 with a SM465 and a weather seized 350.

I love the idea of the 6.2. It has the potential for awesome mpg and diesel consistently cheaper than gas here. The engine is a drop in with some minor wiring and other plumbing. Since My truck is a 1/2 ton I won’t be towing much with it therefore don’t need a ton of power. A local junk yard has a 86 Chevy g30 van that has a 6.2 and they will sell me the engine with all accessories for $300. The catch is the yard owner thinks it has a bad motor but it has been so long he can’t remember if it was that van or the cucv van he has. I can get a rebuild kit for the engine for around $400.

Unfortunately the junkyard van is an automatic so I would have to try and track down a diesel flywheel or some sort of balancer for the engine, if I’m not wrong in my reading. I could probably work out a deal to get the hydro boost setup and some other odds and ends I’ll need to do the truck such as a radiator and some batteries.

I have also located a turbo setup, minus the intake, off of a 6.5 for $100. Not sure if that is a good deal but I have read it is a direct bolt on and gives a power and mpg boost as long as I keep the EGTs under 1100f and the boost 10psi.

I am assuming the 350 in my truck will need to be bored and need a ground up rebuild to be reliable. The truck has been sitting outside for 6 years and I tried to rock it back and forth in gear with my buddy’s truck and couldn’t get it to budge at all. That was after the cylinders were filled of marvel mystery oil for a little over a week.

All I want out of this truck is to be a reliable daily driver and to get good mileage. If I had the money and time I would do a 4bt swap. But I need this truck running before winter hits.

What do you guys think. I need honest opinions. Thank you in advance.

 

[CSFJ]

Flywheels are available for the 6.2's, I got one for a project I had from Rock Auto a couple years ago. That being said, bolting a turbo setup on a 6.2 doesn't typically lead to long engine life. Nor will it increase mpg's. The 6.2 is going to add a lot of weight to the front end of your truck too. Like big block weight, minus the advantage of extra horsepower. Which means addressing the springs that are under the front end, which means more money. I all reality, the cheapest, most expedient way to get your truck on the road reliably, will be to swap in another small block chevy.

 

[hunters628]

Forgot to add. If I stick with the 350 I need to get as close to 20 mpg as I can. I often drive a 400 mile round trip to the coast and back to visit family, 2-3 times a month. Is that even possible to achieve? I would not be able to afford the fuel bill at 12 mpg.

 

[CSFJ]

If mileage is that critical, you'd be better off keeping the truck as a second vehicle, and sourcing something else more efficient to use as a daily driver.

 

[Big Chip]

Did you mean to say “buy a Prius”? Are you feeling ok?!?

 

[yevgenievich]

A stock 6.2 without the turbo would probably work good enough with mpg requirement

 

[Frankenchevy]

Forgot to add. If I stick with the 350 I need to get as close to 20 mpg as I can. I often drive a 400 mile round trip to the coast and back to visit family, 2-3 times a month. Is that even possible to achieve? I would not be able to afford the fuel bill at 12 mpg.

Maybe with a 4.8 LS. My Vortec 350 is fuel injected with ECU controlled timing, a super tight Hughes XTM converter, good gearing for optimum torque at cruise multiple spark discharge ignition box and other optimizing goodies; I might eek out 14-15mpg. Maybe if I had a 4l80e over my th400 and regeared it for the OD I might get 2-3 more. That’s $8k in stuff though. You can buy a corolla and a couple years of gas with that money.

If you were geared right with good tires, wheel bearings and other parasitic loss items addressed with a 6.2/700r4, I wouldn’t think 18-20 would be unheard of. Sounds like that 6.2 may be a gamble though.

 

[CSFJ]

Did you mean to say “buy a Prius”? Are you feeling ok?!?

Yep, that's what I meant. Still getting over some viscous cold or allergy b.s.

 

[82Diesel]

Stock 6.2 easily 20 - 25 mpg. Easy.

 

[Frankenchevy]

Cosidering GM’s provided epa estimate was 22 highway in a four speed, 25 might be a bit of a stretch. Usually car manufacturers are pretty optimistic with their claims, as well. If you were Joe hypermiler and had stuff dialed with an all flat freeway commute...maybe, but certainly not easy.

 

[CSFJ]

Stock 6.2 easily 20 - 25 mpg. Easy.

What else did you ask Santa for this year?

 

[Big Chip]

What else did you ask Santa for this year?

I thought he was leaving for the greener grass over at 47-72?? He did tell us all off and deleted his profile stuff and deleted pictures and posts didn't he? What's going on Kyle?

 

[Blue Ox]

I've been there and done that, but not with a van engine. The van engine has a slightly different configuration so you're going to need the right thermostat housing. It's been a while, so I don't remember if there are differences in the manifolds or not. Accessories and drives will probably be different too. I'm not sure if you can "get away" with it or not, so you might want to consider the CUCV engine instead if it's healthy and available.

The engine itself is just okay. It's never going to be a racehorse, but that doesn't sound like what you're looking for. Make sure you check the block for cracks around the outer main cap bolts. Also, your gear ratio will have a lot to do with how it performs. If you're geared for mileage don't expect it to accelerate much. OTOH, if you have an overdrive you can get the best of both worlds.

If your truck has A/C the turbo will give you an issue with the blower box. Otherwise there should be room. Your numbers for the turbo pressure and exh temp are about right. It doesn't have a major effect on mileage unless you're towing, pulling hills or a leadfoot in stop and go traffic. But if you're not doing any of those things why bother with a turbo?

 

[hunters628]

I've been there and done that, but not with a van engine. The van engine has a slightly different configuration so you're going to need the right thermostat housing. It's been a while, so I don't remember if there are differences in the manifolds or not. Accessories and drives will probably be different too. I'm not sure if you can "get away" with it or not, so you might want to consider the CUCV engine instead if it's healthy and available.

The engine itself is just okay. It's never going to be a racehorse, but that doesn't sound like what you're looking for. Make sure you check the block for cracks around the outer main cap bolts. Also, your gear ratio will have a lot to do with how it performs. If you're geared for mileage don't expect it to accelerate much. OTOH, if you have an overdrive you can get the best of both worlds.

If your truck has A/C the turbo will give you an issue with the blower box. Otherwise there should be room. Your numbers for the turbo pressure and exh temp are about right. It doesn't have a major effect on mileage unless you're towing, pulling hills or a leadfoot in stop and go traffic. But if you're not doing any of those things why bother with a turbo?

Thanks for the info. I would go with the cucv motor since it would be a J code but it’s missing a head intake and exhaust, it has been pretty well robbed for parts. But the cucv motor is in a military van, so it would be the same deal. I will do some more digging on the compatibility.

 

[CSFJ]

No such thing as a military van. The cucv trucks were only pick-up and blazer configurations.