Need power

[75chevyred]

OK , im the new guy here. I got two trucks. One 75  1 ton dually, with a 350 in it, the other is a 85 GMC was a 6.2 diesel , now has a 350 in it also..
Here my problem. I need to tow 10,000 pounds of rock in a dump trailer. Currently the dually is struggling at 48 MPH. It had a 454 originally. th400 ( big one)
 
The 85 GMC can be reinstalled with a 6.2, i have 2 of those bad boys. It has a 400 tranny, short shaft. problem is im not a diesel man.

Any suggestion would be helpful? I dont have a lot of money to spend on these trucks right now

thanks HJ

[VileZambonie]

A 350 can handle it. I'd look more at the whole package here. What's the final drive gear ratio? What happened to the 454? What trans do you have in there? IF you're carting around 10k lb of rock I don't think speed is your concern as you'd probably want to keep it low. I hope you've beefed up your suspension too for this pay load

[75chevyred]

OK, the truck is stockl 1 ton dually, strong springs under the truck. It hold the 2000 pound trailer well. Pulling the 2000 pounds you cant tell its back there. 
The transmission is stock  400 like the bmw type 3 speed,  not the short tailed type. Drive shaft bolts to the tranny, i think its about a 4 incher?

The 350 has headers and a 4 barrel Elderblock intake and carb, still has stock radiator and cooling system seems ok.

I just when throught the brake system, they hold good , Im going to have to put a trailer brake control in the dually to help stop the rig when loaded. Trailer has electric brakes

Ive only pulled the trailer about 35 miles so far , Just brougth it home and parked it so far. The Dually seems to be the truck it with? However, it did backfire about 5 times coming  home under the load

OH, it does NOT have a good breather system on the 350. Im going today and look at a preformance air intake

thank HJ

[VileZambonie]

I had to read your post a few times but don't get what you are saying especially here?

The Dually seems to be the truck it with?
thank HJ

What is your rear end gear ratio? If the engine is stock You might consider a better cam and ignition system too.

[75chevyred]

Basically  i'm saying the truck will pull the 10k but just lacks the power to maintain 60 mph
I have another truck but don't think it would pull 10K
thanks  for you help, i'm working on this problem

HJ

[werewolfx13]

A 350 shouldn't have an issue maintaining 60 mph with a 10k load if its appropriately geared and running properly...

[75chevyred]

OK, I agree, its a 350 with headers, M40 - Turbo Hydra-matic Transmission, Im quessing its a 4:10 rear end according to the 73 - 80 GM Chart

what do  you think?

[Captkaos]

That should pull it without issues with that setup, but you said it backfired when pulling it home?  When is the last time it had a tune up, wires, plugs, etc...

[75chevyred]

actually ive never tuned it, Just adjusted the valves and set the timing to 8 degrees.  I did clean the plugs , oldtimers  method of sand blasting plugs.. the igintion is Malloy , wires  8.8 MM, there nothing out of the ordinally, in that area.. I think the values are to loose now. My neighbor mechanic, suggested the valve adjustment..

Heres a thought, before i bought the truck, it set up a lot and I beleive it got a little water in the top side of the engine  due to a hood leakage. I  change the oil after running it about 30 minutes.. the oil was a little cloudy.  I havent looking in the lower side of the engine, but the motor runs to darn good to be hurt ( I think)
  HJ

[werewolfx13]

Don't just clean the plugs, replace em. They're cheap. I pay <$10 for 8 champion or AC delco plugs, depending on which is on sale at the moment. As for the moisture issue, change the oil and filter and do NOT use any kind of additive, and run it out on the highway for a little bit, long enough to get good and HOT, full operating temp, then cruise it at a steady 10-20 mph with minimal stops for about 20 minutes to keep it good and hot. That should dry the entire engine out thoroughly, if the oil is still milky white, you've got more serious problems (ie, leaking head gasket, cracked head, etc.).

[Captkaos]

You shouldn't ever have to re-adjust the valves on a hydraulic lifter.  What procedure did you use to adjust them?  Having them too tight will cause a loss of power.

I agree on the plugs and oil, buy new plugs and check the gap, and drain the oil and change the filter.

[VileZambonie]

And get a new neighbor! lol

[75chevyred]

heres a question, what kinda MPG will a 1/2 ton (GMC) 6.2 diesel with a th400 3 speed automatic and 311 rear end ,a set of 31x10 15's GET?

[75chevyred]

thanks for all the help on my Dually, Ill get it fixed or sell it later...
Also I picked up a frame and guts of a 86 surburban  4x4 today,  6.2,  tranny is ok the truck came with 273 ratio rear  and front ends,,

[werewolfx13]

A friend of mine has an '82 1/2t 4wd with 4.11 gears, 6.2 diesel and sm465 and gets about 22 mpg in town, and about 26 on the hwy at 50 mph, but with those gears its screaming at 60 and sucks some fuel.