nevadanick
Elko, Nevada
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Joined: 11/25/2007
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I had a 1985 Crewcab dually 4wd with 6.2 and a turbo. It ran well enough for that era. Blew a head gasket at 100K so it went away.
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whisperide
Golden Spike area
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Joined: 09/27/2011
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What's with the obsession about power? There's no law requiring you to have a certain amount, or a certain acceleration.
What's the obsession with low RPM? The 6.2 is perfectly okay being spun to 4200 RPM climbing a long 4% grade, I know because I still do it every week. The HP peak starts at 3600, unlike the Cummins being dead and redlined by 2600.
I have the manual controller for my glow plugs, this is definitely the best way to have it. Just a simple button added to the dash.
'06 GMC C2500HD RCLB gasser 4.10:1, 4L80E, custom camshaft
'84 Trans Am 6.2 diesel, 700R-4, custom Class-3 receiver
'69 F350 dually. GM 6.2 diesel, turbo, 700R-4, NP208 all pending.
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fandango49
Severna Park, Maryland
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Joined: 07/01/2011
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These guys are a good source for parts. I've got 340 HP
Penisular 6.5 diesels in my boat.
http://www.peninsulardiesel.com/WP-PENTEST/
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the_wanderer
texas
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Joined: 10/27/2011
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Thanks for the info. My current rig is a G30 cutaway, 350 engine. I have a chance to buy a bus with that 6.2. Since my transmission failed (700r4) I have been contemplating going with another vehicle. Since I am a conversion guy, I have put a lot of work into this van. I just don't know if that combination (350 engine, 700r4 trans.) is enough to pull my small motorcycle trailer (2000 lbs.) when I get out west in the mountains.
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whisperide
Golden Spike area
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Joined: 09/27/2011
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A most-excellently-built 700R-4 is probably the best investment I ever made. The one I'm using now, this C-20 is the sixth vehicle I've had it in.
Any stock 350 gas V8 Chevy engine is rated to more TQ and more HP than any stock GM 6.2L diesel V8. and adding 50 ft-lbs of torque to the gas 350 is far cheaper and far easier than trying to do the same thing to the 6.2, but the 350 will never get the MPG the 6.2 will.
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Jarlaxle
New England
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Joined: 11/18/2006
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A 350/700R4 will run away from a 6.2 on hills, and that's with the 350 loaded & the 6.2 rig empty! The 6.2 does nothing well except get good fuel mileage empty. It sounds like a wood chipper trying to shred gravel, it has the power of a V6 running on 5, and it has a distressing tendency to blow up when asked to pull heavy loads. In fact, I would rather have a gas six cylinder in a Stepvan than a 6.2 diesel. Unless you're willing to flush the 6.2 for a turbo'd 6.5 (ideally, the Optimiser 6500 Hummvee engine) or gas power, don't even think about doing this. The 6.2 is a bad cold starter if not plugged in.
Also, it will almost certainly have a TH400 with no OD...this means it will be HOWLING on the highway, spinning 3000+RPM to run 60MPH, since most 6.2's were crutched with super-deep gears (my old K-35 had 4.56's, I have seen Stepvans with 4.88's). This makes over 65MPH a pipe dream and 60 loud to the point of pain.
John and Elizabeth (Liz), with 3 nutty cats
My beloved St. Bernard, Marm, lost him 1/2/12
Current rig:
1992 International Genesis school bus conversion
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the_wanderer
texas
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whisperide wrote:A most-excellently-built 700R-4 is probably the best investment I ever made. The one I'm using now, this C-20 is the sixth vehicle I've had it in.
Any stock 350 gas V8 Chevy engine is rated to more TQ and more HP than any stock GM 6.2L diesel V8. and adding 50 ft-lbs of torque to the gas 350 is far cheaper and far easier than trying to do the same thing to the 6.2, but the 350 will never get the MPG the 6.2 will.
How does one add the torque to a 350 engine? And as far as an excellently built 700r4, I've had one rebuild and it failed. That's why I'm stuck now. To wade through all the claims made by transmission rebuilders is impossible. To make a judgement based on unlimited funds would make it easy. Anyway, I think I'll stick with the 350 after the advice I've received.
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SoCalDesertRider
SanDiego, CA, USA
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Joined: 12/14/2003
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I'd rather have a 454 and a TH400 or SM465 4-speed with 4.10's or 4.56's in that bus.
05E350 6.0PSD
97F350DRW 7.3PSD 4x4 4.10 11' flatbed
98Ranger
69Bronco ATC250R CR500
20' BigTex flatbed carhauler
Callen Camper
92F350 CrewCab 4x4 351/C6
B&W TurnoverBall, Curt Magnum V
HD Springs Bilsteins,
285/75-16E BFG AT on 16x8 Stocktons
4.56's & LockRite rear
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whisperide
Golden Spike area
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My 2 best 700R-4s both came from BowTie Overdrives, www.700r4.com, current rate for a stage 2 is around $1500, IIRC. But if you're on a salvage yard budget, then find a NV4500. The stupid old SM465 doesn't have an OD, nor does the far stupider TH400. That's why my C-20's old SM465 is lying under the snow in my yard, rusting. You can't use OD while towing, with a 700R-4 or NV4500, but I'm not always towing.
Getting more torque from a 350 is ultra easy. With a bit of searching, you can score a complete '96-up Vortec 350 long block for under $200 at any of the decent salvage yards. Or you can just put a new pair of Vortec heads on any '87-up short block assembly. The GM part number for the heads is 12558060. These are under $600 / pair. You will need a matching intake manifold.
Then there's the cam, the headers, and the exhaust. The exhaust system must not be restrictive. For decent MPG when not hauling much of anything, the right 2.5" mandrel-bent single exhaust with a truly excellent muffler is the minimum. Single 3" or dual 2.25" is even better, still mandrel-bent.
You should be using 1.625" long-tube headers with 2.5" collectors.
Now, the cam. The safest, easiest, cheapest cam that'll deliver the torque is GM's latest marine cam, also used in the RamJet 350.
Part number 14097395. This will add torque by 1500 RPM, and pull past 5000. It does require the roller lifters, but the Vortec already has them, or if you're at the salvage yards, get what you need from any '87-up car 305.
Depending on your choice of intake manifold, all this together will deliver nearly 390 ft-lbs, with 80% in by 1500, assuming you get the fuel and spark close.
There's no machine work required for this build, no special tools except a common torque wrench.
If you can't do it all, then start with the cam, heads and intake manifold. If you're carbureted, then it's easy. If you're TBI, there is a specific intake manifold, or you can get adapters for carbureted intake manifolds.
If you're already Vortec, then do the cam and headers right away.
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SoCalDesertRider
SanDiego, CA, USA
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Joined: 12/14/2003
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The C6, TH400, TQF727, SM465, NP435 and T18/19 non-overdrive transmissions are some of the most reliable transmissions made in automotive history, so I wouldn't call that 'stupid'. I'd take one of those over an E4OD or Dodge 4spd auto/od any day for reliability and cost of rebuild.
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