The Guy in MY 99TA

whew...I was hoping to see better numbers on these trucks! I found an 03 black burb 2500 4x4 that I'm thinking about purchasing for a hunting truck(planning on doing some traveling out of state).

Any of you guys got a REAL life curb weight? internet says 5,800lbs... that sounds a little on the light side to me.

hog

The 1990 454SS used a th-400 3 speed trans with 3.73 gears and the 230hp@3600rpm and 385 lb/ft torque@1600rpm. It had an EPA rating of 9city/10highway. This was the last application of the MARK 4 BBC and it had 7.9:1 compression ratio.

For 1991 through 1993, the 454SS dropped the 4 speed and stepped up to the 4l80e trans with:
2.48: 1st gear
1.48:1 2nd gear
1:1 3rd
0.75:1 OD ratio.
Now these BBC engine are of the GEN 5 which started in 1991. There were some intake manifold/injector aiming calibration changes allowed for 255hp@4000rpm and 405 lb/ft torque@2400rpm.
the EPA rating for the 91-93 was 10 city/11 highway.
It should be noted that the 88-95 GMT400 trucks that were 3/4 and 1 tons continued with the 230hp/385lb/ft torque version of the L19 engine. Only the SS truck got the uprated 255hp/405lb/ft torque L19 engine.

The GMt 400 trucks now go to the MPFI Vortec L29 for 1996-2000 with its rating of 290hp@4000rpm/410 lb/ft torque@3200rpm and used it in its 3/4-1 ton trucks. There was a 1998-2001 version of the L29 Vortec 454 that was used in the GM heavy duty line of trucks such as Kodiac/P30 van/motorhome chassis, it was called rpo L21.
The Vortec L21/29 were both GEN 6 BBC engines.

The L21 is unique as it is the 1st truck to have CNP(Coil Near Plug) ignition, ETC(Electronic Throttle Control) which is all able to function because of its new 512kb dual 80 pin connector PCM. L21 equipped vehicles have interesting options like a high idle function which is switched via an in cab switch. There is also a idle speed control function that allows engine rpm to be controlled by bumping the switches to raise or lower engine rpm by increments of 25rpm, this is handy forr PTO(Power Take Off) usage.
Then around MY-2000 the L29 and L21 454/7.4 engines
were replaced by the L18 GEN 7 8.1 liter 496 cid BBC, also with CNP/ETC controls. These PTO/Fast idle options exist to this day in the commercial trucks, and in the 3/4 -1 ton Diesel trucks.
Last OEM application of the GEN 7 BBC was in

Chev Performance Parts(formerly GM Performance Parts) offered p/n-12360893- Retro-Kit-truck engine conversion kit CARB/emissions compliant exemption for the 1991-93 BBC equipped trucks.
That part number gets you a HT502 engine and 43 other parts which includes a TBI ECM chip, exhaust manifolds, dual cats-pretty much the 454SS cat and precat exhaust, O2 sensor, 1996-2000 L21/29 roller camshaft p/n-12552296 204°/209° duration at 0.050" lift using 1.7:1 rocker arms with a valve lift of 0.480"/0.483" lift. with an 8.75:1 compression. This retrofit package is only for 2wd trucks, as there will be exhaust interference on a 4wd truck. This illustrates the fact that the exhaust/cat part of the package comes from the the 454SS truck which is 2wd of course. You can get the exhaust to fit, but GM had to be carefull with its wording as the retro package has to me installed 100% using the parets that come with the kit. It will able to be installed on 4wd vehicles.
As installed with all the parts included gets the power rating of: 320hp@4400rpm/515 lb/ft torque@2800rpm and is designed and calibrated to run on 92 (R+M)/2 octane fuel. Kit came with an 18 psi fuel regulator and a new fuel pump 25163473

P/N 88890534, is the same longblock used in the TBI/retro package. It is rated at 377hp@4400rpm-512lb/ft@3300rpm. $6321
Both of these HT 502 engines use forged pistons, forged crank and forged connecting rods that have been shotpeened.

Bigblocks are certainly not known for their fuel economy.

peace
Hog

Ronich69

My '01 Suburban K2500, 8.1L is 8,600lbs

Kerr

I think my title said 8K with all my other crap im over 9300. at least thats what the scale said at the race track..


unless you go diesel excursion you will not find a better tow suv.

Get the sway bar thing that attach to hitch if you need and let it eat.. The mileage sucks but you can hurt a 8.1L and in real world its only about 2-3 mpg worse than a 6.0L. thats compairing mine stock to the crew cab truck stock, towing wise there is no comparison.

The 6.0L crew short has 4:10 gears and its either 3K rpms or 6K rpms when you hit the hill. the 8.1 stays around 22-2400 and it has to be a huge hill ( montain) to get it to down shift..

Leewman

I get 10-11 around town. And 12.5-13.4 on highway.
I have 3.73's, 35's, Diablo tuner, magnaflow exhaust.
I am aggressive when need be. She is a turd off the line. My old supercharged Tacoma would smoke her till 25 or so. Then the BigBlock wakes up.

2001 suburban 2500, 8.1.

RezinTexas

My last tank got 7.0 mpg. The bitch is thirsty!