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Username Post: mid 80s towing package?        (Topic#363297)
kangaroo 
Member
Posts: 278

Reg: 11-04-06
11-15-20 07:19 PM - Post#2807836    

What upgrades should I be looking at for a mid 80s truck with a 350/350 , 76cc heads and a rv cam?

I towed my trailer with a cord of wood this weekend and it seemed to be missing some power. Stopping was fine and getting moving was slow and easy. The temps moved up from normal driving to 200 degrees over the 45 minute drive. I must have been going over a incline at one point because I seemed to have given it more throttle , because the truck seemed to be slowing down, and nothing. The truck kept moving forward but giving it more throttle did nothing. Besides getting to drastic and changing heads or engine , is there any other items I should be looking into? It has the stock intake and exhaust also .



 


scrambldcj8 
"2nd Year" Silver Supporting Member
Posts: 2601
scrambldcj8
Loc: Belchertown, MA
Reg: 04-06-03
11-16-20 03:35 AM - Post#2807845    
    In response to kangaroo

How many miles per year (estimate) do you drive it....long/short distance?

Auto/manual? What gear ratio/tire size....it maybe less costly (?2wd/4wd) to go to a lower ratio if you use it infrequently like in town for hauling.

How does she run otherwise?



 
gchemist 
Member #271 Senior Chevytalk Moderator
Posts: 25304
gchemist
Loc: Austin, TX 78748
Reg: 05-09-00
11-16-20 11:03 AM - Post#2807872    
    In response to scrambldcj8

Well, 155 HP if all available is not going to get you anywhere fast. Double to 300 HP so it can move faster. Free up HP by free flow exhaust, ditch the mechanical fan for electric, and drop the operating temp a little.

'83 Silverardo XST - ZZ4 powered
'95 Jimmy SLT (Bought @131,814)
'96 GMC Jimmy LS Ret. @236651 miles
'08 GMC Acadia 3.6L SLE


 
Rick_L 
Member #409
Posts: 27781
Rick_L
Loc: Katy, Tx, USA
Reg: 07-06-00
11-16-20 07:37 PM - Post#2807905    
    In response to gchemist

More gear is going to help. That RV cam isn't doing you any favors without more gear ratio.

Your other biggest problem is low compression ratio.



 
scrambldcj8 
"2nd Year" Silver Supporting Member
Posts: 2601
scrambldcj8
Loc: Belchertown, MA
Reg: 04-06-03
11-17-20 03:08 AM - Post#2807917    
    In response to Rick_L

^^^ Exactly my thoughts. The OP doesn't want to/or cant do major surgery on her, and if she runs OK for her age....I say gear change to get that oomph ie: Torque. It's in the math...LOL

The above suggestions of exhaust and E-fan will certainly help, but by how much he'd actually feel/gain I am not so sure. $$ vs payback

The comp ratio here is a big player. Any loss of cylinder pressure will have a reversal effect if duration/overlap are increased with another cam change...depends on lobe separation though. Basically,less overlap, you need less duration and/or more lobe separation.



 
1983G20Van 
Super Senior Member
Posts: 3829

Loc: Bedford, Texas, USA
Reg: 11-13-02
11-18-20 02:32 PM - Post#2808028    
    In response to scrambldcj8

Having worked on a few of these engines the best thing a person can do with a smog 350 or even 400 with 76cc heads is use them for a door stop or boat anchor and put some TBI or Vortec heads on the engine. I pulled a stock 350 apart in an 80s G-van based motorhome that pulled a fairly heavy boat. It had 76cc heads with 1.72/1.50 valves. Put a set of Vortecs on it with a performer intake keeping the Q-Jet and added a set of thorley tri-y headers. Also swapped the cam to a Mellings MTC-1 the little 204/214 RV cam. The RV felt like it had twice the power and got better fuel mileage. No more crawling uphill in 2nd gear or even 1st gear.

Swapped the 350 for a 400 with TBI heads and a Comp HE 260 cam into a 95 G30 based RV as well a couple of years ago. Made ALOT more power than the stock 180 HP 350 TBI. Made about 300 hp @ 4,000 rpm and close to 450 ft/lbs at 2,500. With the factory 4L80E and 4.56 gears it would pull the RV and a 4,000 lbs boat uphill at 70 mph in OD. Where the stock 350 struggled to maintain 45 mph in 2nd gear the 400 would pull 3rd at 70 mph. Fuel mileage went from about 8 mpg up to about 11 mpg towing and moving the same vehicle.

I tow a travel trailer with a 350 Vortec and 4L85E in my Express van. Had a 395' marine cam in the 350. Made an honest ~330 hp and 400 tq. I could tow uphill at 70 mph in 2nd gear. I swapped an aluminum head 383 making close to 500 hp into it and a 5.13 gear. I can run up the same hills in overdrive at 2,850 rpm now. With the 3.73 gear I NEVER used overdrive towing. That was 3,000 rpm @ 70. Now I turn 2,850 in Overdrive and actually get better mileage. Underpowered stuff will always suck gas.

1983 G20 Van, 350 TPI, Ported 906 Vortecs, Edelbrock 3817 Base, ASM oversize runners. Reed Custom Roller cam, 700r4, 12 bolt with 3.08 gears, Doug Thorley Tri-Y headers, true duals


Edited by 1983G20Van on 11-18-20 02:43 PM. Reason for edit: No reason given.

 
1983G20Van 
Super Senior Member
Posts: 3829

Loc: Bedford, Texas, USA
Reg: 11-13-02
11-18-20 02:51 PM - Post#2808032    
    In response to 1983G20Van

I also swapped a LQ4 6.0L and 4L80E into an 87 G20 van that had a 305 TBI and TH400 backed to a 3.08 gear. The 305 had 104K miles on it when pulled and ran extremely well. Best it saw on a good day was 16 mpg. The LQ4 has a set of 862 casting 5.3 heads on it that were ported and have a 2.00" intake valve. Also decked them 0.020". The LQ4 now has heads that flow much better and it is about 10.5:1. Added a cam that is about 218/226 @ 0.050. It pulls that G20 van down the road effortlessly at 1,800 rpm @ 70 mph and has seen 20-22 mpg numerous times. I know one day sooner than later I am going to get myself a hell of speeding ticket passing on 2 lane roads. That 6.0L will catch 2nd gear at 80 mph and spin to 6,500 in the blink of an eye which is over 100 mph. Even running 60-70 mph and downshifting to 3rd will put it over 100 mph going around a car.

1983 G20 Van, 350 TPI, Ported 906 Vortecs, Edelbrock 3817 Base, ASM oversize runners. Reed Custom Roller cam, 700r4, 12 bolt with 3.08 gears, Doug Thorley Tri-Y headers, true duals


Edited by 1983G20Van on 11-18-20 02:54 PM. Reason for edit: No reason given.

 
kangaroo 
Member
Posts: 278

Reg: 11-04-06
11-22-20 08:00 AM - Post#2808323    
    In response to scrambldcj8

  • scrambldcj8 Said:
How many miles per year (estimate) do you drive it....long/short distance?

Auto/manual? What gear ratio/tire size....it maybe less costly (?2wd/4wd) to go to a lower ratio if you use it infrequently like in town for hauling.

How does she run otherwise?


Its my second vehicle. To pick up material from the hardware store, take trash to the local dump, drive up into the woods to camp overnight. So its not driven much but would like to keep dependability as my main priority. I would also love to use it to pull a small boat or camper across the state on holidays. Saying all that , I would love some more HP.....

I have couple options now. The engine has about 150k miles max on it right now if that. Its a 350/350 combo.

Option one is get some NEW old bolt pattern heads (brodix heads) that Grumpy Vet recommended me a while back. Will need Heads (1200$), gaskets (100$) , alum. intake(175$), headers (150$), mufflers (100$). Possible cam (200$)
1725-2000$ total


Option two , get vortec headed engine (I have this engine sitting in garage) rebuilt (1500$), alum. intake (350$), gaskets (150$), headers (150$), mufflers (100$). Possible cam (200$)
2450-3k$ total

Looks like option one would be the budget friendly route , comparing the two. I would like to keep the cost a low as possible , and the build as SIMPLE as possible. I would need to keep all my accessories running in top fashion ,AC, charging system.

Thanks for any help and recomedations. I have been wanting to upgrade this truck for a while .






Edited by kangaroo on 11-22-20 08:05 AM. Reason for edit: No reason given.

 
wagonman100 
Site Ambassador
Posts: 14811

Loc: Baltimore, MD
Reg: 11-27-04
11-22-20 11:59 AM - Post#2808339    
    In response to kangaroo

Just remember with the second option you get a fresh engine with no miles and purpose built.

Jay
Friends don’t let friends drive Fords.

1999 Silverado Z71 4X4 extra-cab short bed
1983 Malibu Fauxmad - tubbed
1978 El Camino Kustomized
1972 Monte Carlo
1957 210 handyman wagon
1957 Nomad sport wagon
1957 Cameo Carrier


 
scrambldcj8 
"2nd Year" Silver Supporting Member
Posts: 2601
scrambldcj8
Loc: Belchertown, MA
Reg: 04-06-03
11-22-20 01:23 PM - Post#2808347    
    In response to kangaroo

  • kangaroo Said:
Besides getting to drastic and changing heads or engine , is there any other items I should be looking into?



Wow, we've really done a 180 here haven't we?? Now we are Ok with major changes/upgrades...LOL

Swap in a 4BT and turn the screws a bit...that'll make her a little work horse


PS: And I skipped right over your 350/350 originally stated when I had asked about auto/manual above...OOPS!



Edited by scrambldcj8 on 11-22-20 01:27 PM. Reason for edit: No reason given.

 


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