Towing and sucking gas like crazy.

[SUBURBAN5]

My bad,, you're right, it does look like an 8 lug.
Wouldn't a 2500 8 lug have a GVW of ~8,600?
Anyway, 3.73 is too tall of gearing for a small block GMT400 that has to tow very much weight.

I would think somewhere around that range. I agree though 7.4 and 410. Especially for towing. 4wd trucks had 5.7 with 373. Mine is 5.7 with 342. But both applications wernt towing rigs. Just light duty... also that's 1500 not 2500. Having 2500 he should have a more beefier drive train

 

[Gibson]

OK, wrong again.
In post #13 the OP says it's a "semi-float" axle.
If so, then it's a "light duty" 2500, probably with a 7,200 GVW.
Over on some forums about RVs and towing it's generally thought that small blocks need gearing that starts with a "4" to be effective at towing much weight.
Hey,, I know we all love our old 400 platform trucks, (or we wouldn't be here,) but even the last of the Vortec 350s are only about 255 HP, with ~330 Torque in stock form.
That's not much for a heavy vehicle and with only a 4 speed trans none of them are heavy haulers by todays standards.

 

[SUBURBAN5]

7.4 vortec with 410 gave you the most hp and torque for gas right?

 

[L31MaxExpress]

I was going to suggest a Vortec swap; either 5.7 or 7.4 should handle that load. If this is a dedicated tow rig, probably go with the 7.4, but if it's a daily driver 5.7 would get better gas mileage (km?) unloaded.However, loaded both are probably equal, around the 8mpg range.

The 6.0 would get about same mileage loaded, and TQ is between the 5.7 and 7.4, but HP is higher at higher rpm by just a bit.

Any swap is going to set you back $2k to $3k on the low range. Maybe less on the 5.7/7.4, maybe more on the 6.0. just something to consider.

I found my dressed 8.1 with 80K miles on it out of a party van bus for $700 a few years ago.

 

[L31MaxExpress]

7.4 vortec with 410 gave you the most hp and torque for gas right?

8.1 was the highest hp and torque gas for a GMT400 and made a fair bit more torque than even the 454.

 

[SUBURBAN5]

For Kodiak? Or actually silverado setups?

 

[L31MaxExpress]

For Kodiak? Or actually silverado setups?

While Kodiaks came with them later, I am talking GMT400 based 01-02 3500HD.

 

[SUBURBAN5]

Didnt know that... sounds cool though

 

[Supercharged111]

OK, wrong again.
In post #13 the OP says it's a "semi-float" axle.
If so, then it's a "light duty" 2500, probably with a 7,200 GVW.
Over on some forums about RVs and towing it's generally thought that small blocks need gearing that starts with a "4" to be effective at towing much weight.
Hey,, I know we all love our old 400 platform trucks, (or we wouldn't be here,) but even the last of the Vortec 350s are only about 255 HP, with ~330 Torque in stock form.
That's not much for a heavy vehicle and with only a 4 speed trans none of them are heavy haulers by todays standards.

This is uncorrect. Full float was an option on the 2500 trucks. Semi float 8 lug is rated to 6000#, semi float 6 lug 2500 rated to 4600#.

 

[Gibson]

This is uncorrect. Full float was an option on the 2500 trucks. Semi float 8 lug is rated to 6000#, semi float 6 lug 2500 rated to 4600#.

Are you saying that the semi-float/6 lug 2500s only had a GVW of 4,600lbs?
I would imagine that an empty truck would weigh that much.
Maybe I'm wrong on this, but weren't the 6 lug semis on 1500s, while the 8 lug semis were for 2500 "light duty", and the full-floaters were for the 8,600 GVW trucks.