Anyone runnung Sub/6.2/465/205?

[hillbilly deluxe]

I have been wanting to do something different with my motor for a long time. The stock 350 just won't pull the truck up mountain passes without impeding traffic... I have been thinking alot about diesel. The mileage is one thing that attracts me. I like the rest of my drive train the way it is so I was wondering if anyone is running a Suburban with a 6.2, 465 and a 205. Looking at the power figures though, the diesel doesn't look any more powerful than the 350. I'm sure the torque comes on alot sooner. I don't want to swap in a motor that isn't any better than the one I have now, or swap in a motor that doesn't work well with my drivetrain.

Opinions?

 

[Russell]

Esspecially up high in the mountains, you are not going to have better luck with a naturally aspirated diesel engine vs your original gasoline engine. Diesel engines are only limited by how much air you can move through them, and since you are at a fair elevation where there isn't nearly as much air, you are still going to be going slow, but chugging black smoke out and melting pistons because of it, haha

On the other hand, if you were to turbocharge said diesel, you could see some pretty huge performance increases. When I used to take my naturally aspirated 6.2L up to 2000 ft elevation to go wheeling from our natural 700 ft locally, I'd have a totally gutless engine that smoked worse than an old freight train with any amount of throttle on it. Once I started taking a turbocharged engine out that way, I have noticed some degree of slowdown, but have been able to up my boost a pound or two without increasing my exhaust temperatures to regain all the power I'd lost.

That said, there is no good reason why your 350 should be an impediment to traffic in the mountains... I used to take my old C20 with a 350 / TH400 out to the mountains all the time, and while it did loose a noticeable amount of the seat of the pants feeling, it never slowed down on any climb unless I was trying to conserve fuel.

Is your carb tuned for your elevation? 4 barrel or 2 barrel? HEI or points? Any engine modifications, or is it bone stock?

 

[hillbilly deluxe]

It's stock. I replaced the distributor and the carb recently because the old ones were shot. The distributor is HEI and came with a hotter coil, the carb is a remanufactured Quadrajet from jegs. I have headers and and dual exhaust but I doubt that adds more than a few hp. It weighs 6k. It has 4.10s. As far as I can tell it's the original engine (rebuilt obviously). I checked the serial number on the carb and it said it was from a 73 truck with a manual trans.
I looked at all the parts to make my 350 a stroker on Jegs. About 2 grand without any machine work included. Then I found some Banks kits for the 6.2 for 2k on the internet and see 6.2s for around a grand all the time. So I came to a ballpark estimate that I may be able to do either for 3k. The stroker may be more powerful, but the diesel may yield better mileage. I need help...

 

[kennyw]

The 6.2L with a turbo will give far better mileage. While you could do it all for $3K, you can do the same thing for $1500 if you shop around for good deals on parts. A good running low mile 6.2L should sell for under $500. You can pickup rebuilt motors from the gov auctions for less than that, but you have to be careful because they are not all rebuilt motors, some are junkers tossed in the shipping crate after they replaced the motor.

 

[Russell]

Do you happen to know approx what your elevation is?

You may need to play with the hangers or rods, and the power piston within your Q-jet to lean things up a bit. Generally speaking, lean is mean, but you don't want to go so far that you throw your exhaust temperatures through the roof and have problems with overheating, or melting things.

If your carb is set for a 350 running at sea level (probably not, but just as an example), it'd pretty much be blowing black smoke at 6 or 7000 feet of elevation if the rods were not increased in size, dropped further into their jets, or had smaller jets installed period.

Power piston spring tuning (for part throttle performance) is best judged by the seat of the pants feeling, but can be done with a vaccum gauge as well.

I betcha that tuning your carb up for your environment would likely help a whole bunch. Hotter spark plugs / ignition components probably help if your engine is running rich all the time, but what you've got shouldn't need any additional upgrading... I know the concept of setting up a q-jet is scary buisness (most of the reason why I went 6.2L in the first place, haha), but when one is set up properly, it can get you as good of mileage as a TBI engine does, and have fantastic power all across the board.

 

[hillbilly deluxe]

Colorado Springs is at 6000 ft. Most places I go wheeling and camping are at 8000-10000 ft. I honestly have no idea if the carb is tuned for this elevation. I doubt it. When I ordered it from Jegs they siad it was tuned for a truck, but they didn't mention altitude. It really doesn't run poorly at that altitude, then again I am rarely going very fast at that altitude. This pic is about 9000 ft.

 

[Russell]

Well, at that altitude I'd definitely suggest buying an air fuel monitor and see where you are running most of the time. You don't need a wideband sensor by any means, just a rough guide.

If things look normal, well, you've got an extra gauge to watch for the fun of it, if not, it'll be instrumental in helping to set your q-jet up properly

 

[hillbilly deluxe]

That's a really good idea Russell, I am going to look into that. The more gauges the better I say.