4.3 liter heavy duty version

[Billgmcallen]

In my quest for knowledge about the gmt400s I've came across multiple incidences of a 4.3 liter heavy duty version which came on 2500s with 8500 pound gvwr and above. It had 5 less hp than the standard duty 4.3 and 5 less lb torque. Does anyone know the difference between the two? Im curious because i have a 4.3 and if there is a way to get added durability then im all over it.

 

[Wagonbacker9]

I am unaware of a 3/4 ton ever receiving a V6.
There are 2 versions of the 2500, the light duty with 6 bolt hubs, and the heavy duty with 8 bolt. Both came equipped with a 14 bolt semi floater rear axle.

 

[Billgmcallen]

yes i am aware of that, i am also aware of the f44 rpo code for half tons which received the semi floating 14 bolt, extra leaf springs, larger brakes front and rear with hd front hub assemblies. and yes you could get the 4.3 in 2500s but not 3500s.

 

[Billgmcallen]

http://www.pickuptrucks.com/html/stories/history/1973-to-1998-chevy-pickups/part2page2.html

check the second page of that. i also have a Gm heritage center 94 page document all about the 93 model year which talks about the 2 versions of the 4.3 liter.

 

[90W7]

I though a 305 in my 6 lug k2500(7200gvw) was bad enough. I can't imagine a 4.3 .. Interesting tho.

 

[someotherguy]

Might have been slated for production but doesn't mean they actually did it. Haven't ever seen or heard of one in the wild. Would be a gutless wonder, for sure.

Richard

 

[Billgmcallen]

My dad worked in construction for some refineries ect and said some of their fleet trucks were 2500s with the v6s. That's why he bought mine with the v6 because they took a lot of abuse and held up well in his opinion. I really like my 4.3 great fuel mileage, I've never had a problem towing either but just a curious though to wonder what the difference between the hd and ld model was.

 

[90W7]

I would assume if orderd as flees vehicles then they could have got them with the 4.3

You saying the heavy duty 4.3 has less hp immediately brings to mind the differences between a 8600 gvw 350 and a 7200 gvw 350.

The 8600 having 4 bolt mains and lower compression.

The 7200 and lower having 2 bolt mains and higher compression.


I'm not sure if those differences applied to the 4.3 engines also. The only addition other than what I mentioned above to make the 4.3 "heavy duty" and especially this being more geard towards fleet vehicles would be

1. lower differential gears
2. Upgraded/larger oil and transmission coolers.

 

[Birchyboy]

FWIW, RockAuto lists the 4.3 under the 1994 GMC K2500.

 

[skylark]

I had a 91 Light duty SCLB C2500 with the 4.3. It was an ex Lincoln Co, OR school district truck. They used to run S10's but they needed something bigger so they bout the 2500's. They had 4-5 at the auction where I bought it in 98 or so.