4.3 for towing

[retiredff]

Hello, new here. I'm a retired old dude with a '96 GMC full size PU (stock), Tow package with 180k and have used Amsoil with dual bypass since 35k. No issues that I can tell except for a main crank seal leak. Body good to excellent, I added spray in bed liner and sun roof. What i would like to do is update or buy short block and build a 4.3 to tow a 17' travel trailer (toy hauler) that will carry my Harley. What mods should I do to make this 4.3 tow 5000 lbs. and still get decent milage. I get 20 highway/16 city. When towing a small popup I get 15 or so. Any info/links appreciated.

Thanks

Tony

[rabidbandit]

Check out the sticky "V6 Bolt-ons" for some great info! But I would forget about mileage on the full-size...you won't get any better than that I'm afraid:) Upgrade your trans with a shift-kit/servos for a firmer shift while towing...and it may net ya some better fuel efficiency:)

[rentedmule]

I'd worry about your tranny long before the 4.3. My family's business has used full size chevs with 4.3's as parts haulers since they came out and the only issues we ever run into are with the tranny. we usually sell the trucks with 250-300k miles on the origonal engine but we always go through 2-3 trannys in that time.

[Mikz86TA]

Assuming its an auto.
Have the tranny rebuilt and updated with some of the newer HD parts. Use a mild shiftkit with Servos (both 2nd and 4th) and TV Boost Valve. Get an external cooler added in line and a deep pan for extra capacity. Get also the Lo-Rev boost valve and a 7 or 8 clutchpack for the 3-4 clutchpack set.
Find out what gearing it has right now. Id go with 3.42s for best all around.
The 4.3 as a motor is more than capable for your needs. However maintenence is always the factor. Tho it sounds like its well maintained. The cams in them are more low-end anyway. Intake ,exhaust and some other mods would help if you seek more power. What type of injection/fueling system does this truck have?

Welcome To The PLANET!!!

[retiredff]

Thanks for the replys.

The tranny was rebuilt about 10k ago. I have the trailer package that includes an oil/tranny cooler.

Mikz,
The fuel system is TBI.

Will an E-Fan help the milage and different pulleys I read about and will it cause problems while city driving?

I can add headers/pipes and upgrade the air cleaner as they are stock. I will read the sticky and come back if I have more questions.

Thanks again


Tony

[rentedmule]

I had UD pulleys on mine for a while and I didn't have any charging problems - just make sure to get a set like the March power and amp series that comes with an alternator pulley to offset the crank underdrive.

headers don't provide alot of gain for the cost but they don't hurt either. a bigger exhaust, high flow air cleaner/intake, e-fans and the pulleys will make a pretty noticable difference in power and mileage for sure. throttle response will be the most noticable change, it'll just feel stronger (at least that's what I thought with my truck before the supercharger)

[retiredff]

TBI is 2 injectors inside the throttle body, correct? If not what is CFSI?

Tony

[Jay-Sliver]

TBI, yes, Throttle Body Injection. 2 Fuel Injectors, sitting on the top of the engine. Remove your air cleaner, and if its TBI, there will be 2 pods right on top of the engine, 2 wires running to each of the pods. With the truck running, you will wee the fuel spray pattern as the injectors pulse. Make sure (if you have TBI) that these injectors have a consistant fuel spray pattern. Should be cone shaped.

[hero dave]

hummmm.... supercharger?

[Mikz86TA]

If you have an air cleaner like a Carb, than its TBI.

TBI can benefit from a TB Spacer like a carb. There are also spacers that raise the injectors up to allow more air to pass under them.
TBI Inj Slacer = http://www.jegs.com/i/JEGS/555/15410/10002/-1
TBI TB Spacer = http://www.jegs.com/i/JEGS/555/15400/10002/-1
TBI SubStack=
http://www.jegs.com/i/Hypertech/533/4001/10002/-1
TBI intake = http://www.jegs.com/i/Edelbrock/350/3713/10002/-1
Always check with your year and application. But these are popular TBI mods.

[the fabricator]

i had a 1990 full size witha 4.3vortec automatic. pulled a trailor with full size chevy's on it all day long. i tried to blow the engine up but never could. really strong engine period. i wanted to install a 454.:D the 4.3 have unbelievable torque which is great for towing.this truck also had over 300,000 on the tranny and engine. niether had been rebuilt.

[the fabricator]

the only problem i see is if your towing with a s10 is that these trucks are not meant to tow anything heavy. frame,suspension ect isnt built heavy enough....

i suggest getting a hitch reciever that bolts to the frame and helper springs for the rear end/

[retiredff]

I have TBI.

Tony

[retiredff]

the fabricator,
I have a full size GMC 1500 extended cab. My main problem now is it's really sluggish when towing a 5x10 lawn care trailer with a 52" ZTR and 36" walk behind. The mowers weigh total about 1500#. I'm afraid if I try to tow a 4-5000# TT, it will choke! The truck is in great shape and would rather upgrade the motor than buying new/used and have a payment. I'm semi retired and the funds are limited.

Tony

[Bone Crusher]

Pulling my 20' boat of 3000lbs with no problem. I upgraded the tranny with a trans cooler, transgo shift kit and the vette servos like mike said earlier.

[Jay-Sliver]

Gotta get more air in, and more air out. Open up your intake a little, get a high flow filter kit for it. Also, indoing so, take care of the back half, slide on some kind of a performance, low restriction Muffler. With that being said, what style of a converter is on it? Were they still using the bead style, or did they go to the honeycomb kind? Possibly think about putting a high flow performance cat on it if its the honeycomb style. I think the high flow cats are only about $100, and thats canadian funds..
Contrary to us with out truck, you're full size will benifit from having a throttle body spacer. Mikz86TA posted a couple good links for throttle body modifications.

Jay

[Jay-Sliver]

Gotta get more air in, and more air out. Open up your intake a little, get a high flow filter kit for it. Also, indoing so, take care of the back half, slide on some kind of a performance, low restriction Muffler. With that being said, what style of a converter is on it? Were they still using the bead style, or did they go to the honeycomb kind? Possibly think about putting a high flow performance cat on it if its the honeycomb style. I think the high flow cats are only about $100, and thats canadian funds..
Contrary to us with out truck, you're full size will benifit from having a throttle body spacer. Mikz86TA posted a couple good links for throttle body modifications.

Jay

[Jay-Sliver]

Srry...I blame the double post on my Dell...

[Mikz86TA]

On TBI a TB Spacer will add some torque. Id also check out what gearing you have. If you got a 3.08 or 3.23 or higher (numerically lower) then your would be best suited for a gear swap like a 3.42 or 3.73

[retiredff]

Mikz,
The spacer links you posted did not say they were for a '96 4.3. As long as the motor is a 4.3 will they still work?

Tony

[the fabricator]

really sluggish < not the engine but sounds like your transmission is really tired and needs a rebuild or upgrade as already mentioned...


high flow performance cat alot of people do overlook the cat convertors. i recommend removing these completely, knocking out the inside honey cone center or replacing it with a high flow like mentioned. when these get clogged up they cause all kinds of trouble. i have had several problems with them. bog down the engine, cause the engine to overheat and pop the head gaskets. :shake_125

cat convertors are just goverment regulation headaches. get around them if you can or it will cost you later down the road.

the engine in my full size was bone stock....i got checkin into my records and i did have the transmission rebuilt with a towing package type of deal. i forgot all about that. it was such a long time ago. hope this information helps you.

BTW. the full size chevy;s i was pulling was 1958-1965 hardtops, convertibles and wagons...most with BBC's/ no problemo except for stoppin. i never upgraded to bigger brakes. lol

[Mikz86TA]

That link was just for an idea of whats availible. There were 2 different TB units I think. One had a single air cleaner stud and the other had dual stud and wing nuts.
CFM-Tech makes some TBI stuff. Their spacer is for 4.3/5.0/5.7 and Single Stud. Runs aboud $83
JET , Crane , PowerAid , Helix , etc. are some to look into. Just check for sure your year, engine and stud arrangement for the correct one.
TB Spacers only improve performance on TBIs and Carbs. Youll read alot of bad things about them on the CPI applications. Just a rule of thumb...if the air and fuel is mixed Before the spacer, then you will have some gains. Most gains are torque since it effectively lengthens the passage of the air/fuel mixture.
Heres a TwoGuys Episode on a like vehicle with TBI and the mods they did. http://www.twoguysgarage.com/episodes/index.php?epi=410

[retiredff]

the fabricator,
My tranny was rebuilt with stock parts. The cat was replaced with what ever cheap crap Midas uses. I may look into:

- flow-master system and add a hi flow air cleaner (single w/crossover or dual seperates?)
- TBI spacer and different pulleys
- re-manufactured long block
- roller rockers

Any idea what these mods would do to the towing ability and fuel milage?


thanks

Tony

[sammy]

Just to throw more confusion in here.. I have the cpi and a 200r4 tranny. I pull an 18ft. fish & ski boat with no problems. It has a single flowmaster and a k&n airfilter. Once, I pulled the boat out of the water (on the trailer) when the boat was nearly full of water. It nearly sank before I got it on the trailer. 4 wheel disk brakes are my recommendation. Make sure you can stop before you go.

[rentedmule]

the fabricator,
My tranny was rebuilt with stock parts. The cat was replaced with what ever cheap crap Midas uses. I may look into:

- flow-master system and add a hi flow air cleaner (single w/crossover or dual seperates?)
- TBI spacer and different pulleys
- re-manufactured long block
- roller rockers


The flowmaster's sound great but they don't flow as well as other performance mufflers. The difference is minimal and probably not worth worrying about but I just thought I'd throw that out there to stir the pot :p.

The mods you list will only increase torque and mileage so you should be all good. Even a supercharger will noticably increase fuel mileage if you keep your foot out of it. the only thing that would really hurt torque would be a cam designed for higher RPMs or a massively over-sized exhaust.

[retiredff]

Thanks for the replys. I tossed around the idea of a new (2008) truck, but the idea of a payment sucks! My '96 GMC FULL size is in good shape w/tow package, doesn't burn oil, have used Amsoil w/dual remote filters since 28k and now have 175k, Rebuilt tranny (stock parts), everything works, I just need a little more umph when towing. I would like to dump the 60/40 front seats for buckets but thats another project for later.
I found a lot of good info here, I will be lurking and asking questions as I need help.

can anyone recommend web sites for the items I listed (headers,pulleys,TBI spacer,mufflers etc)?

I double checked to be sure my motor is a TBI (it is, the fuel line connects and exits behind the throttle body, no injectors found anywhere) and found what appears to be the EGR valve located on the back drivers side of the header and plugs into the intake just forward of the TBI. Is this what can be removed/plugged? It appears to be connected to the exhaust manifold with a 2" or so section of pipe. It is covered with some type of hose so I cant tell for sure. I'll take some pic's and post them here if possible?



Tony

[retiredff]

I was on 2 guys garage and found the TBI spacers for everything EXCEPT for a 1996 4.3 v6 GMC 1500 full size pickup. Is this a bastard or what? The only thing I found that might be for my 4.3 is they list air cleaner types as single or dual wing nut bolt on. Mine is a single so I would assume this would work. Is the "swirl" thing hype that is listed for towing or is a standard spacer fine?

Sorry about the questions, my day for working on cars was the (gulp) '60's.

What does "cat back" mean for muffler systems?

My VIN says the type is "W" (air cleaner is attached w/1 wing nut)

I had a 57 coupe I would love to have back!

Tony

[Bone Crusher]

means it bolts up to the catalytic converter all the way back to the tip which generally has a muffler in between

[retiredff]

Thanks Chris. Things sure have changed in xxx years!:shake_125

Tony

[bespurcell]

http://www.summitracing.com/ This is a good site.