95' L99 into 93' Chevy Truck

Hello! New to group. I have a restored 93' Chevy 1500 with a 4.3 V6, and 4L60E trans. I recently bought what I thought was a 95 LT1. To my chagrin, it is a " baby LT" L99 4.3 V8. The wiring harness looked mostly complete with PCM. My confusion , just one of, is that the PCM says 94-95 B or F body LT1. Gonna be needing a lot of help on this as I am used to running a OBD1 TBI motor, and new to all this LT stuff. But that's why we do this stuff, it's a challenge. Possibly gonna need new harness, and most definitely a program for the OBD1 95 programmable PCM. Thanks for adding me to this group, as I do know Dynamic EFI is a reputable company.

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Originally Posted by EscottB

Hello! New to group. I have a restored 93' Chevy 1500 with a 4.3 V6, and 4L60E trans. I recently bought what I thought was a 95 LT1. To my chagrin, it is a " baby LT" L99 4.3 V8. The wiring harness looked mostly complete with PCM. My confusion , just one of, is that the PCM says 94-95 B or F body LT1. Gonna be needing a lot of help on this as I am used to running a OBD1 TBI motor, and new to all this LT stuff. But that's why we do this stuff, it's a challenge. Possibly gonna need new harness, and most definitely a program for the OBD1 95 programmable PCM. Thanks for adding me to this group, as I do know Dynamic EFI is a reputable company.

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L99 4.3 V8 is based off the LT1 setup and uses the same PCM although a different calibration than the LT1. Most B-cars seem to have $EEB files. Should be a 4.3 file on this site if you need one. 4.3 V8 will run smoother and make more power than that 4.3 V6 that was under your hood to start with. Its still a V8 and will respond to basic hotrod parts. Headers, small cams, tuning, etc.

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Originally Posted by Fast355

L99 4.3 V8 is based off the LT1 setup and uses the same PCM although a different calibration than the LT1. Most B-cars seem to have $EEB files. Should be a 4.3 file on this site if you need one. 4.3 V8 will run smoother and make more power than that 4.3 V6 that was under your hood to start with. Its still a V8 and will respond to basic hotrod parts. Headers, small cams, tuning, etc.

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Thanks. Any good info is helpful. Got a lot to learn

Thanks. Any and all good info is helpful. I have a lot to learn, but hard work doesn't scare me.

I will be glad to see a virgin l99 bin file. If you can read the pcm please post it here.

You need a basic aldl cable and EEhack program. It is available for download here. It will help you to tune, log and flash your PCM.

That 3" stroke crank and its 5.94" rods can be dropped into a 350 block with 4" bore 350 pistons to make a 302 sbc. RPO L99 was rated at 200hp@5000rpm/240lb/ft torque@2400rpm.
It uses the same cam that the iron headed B-body GEN 2 SBC LT1 used. The L99 was the standard engine in the 94-96 Caprice only.

peace
Hog

GM did an interesting build on one of those L99 265s to put into a 1955 Chevy back in 1995. They used the Hotcam and IIRC LT1 aluminum heads. Made about 330 HP @ 7,000 rpm. They backed it to a 4L60E with a loose converter and deep gears. Made an interesting tribute to 40 years of small block design by going back to the first small blocks 265 cid.

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Originally Posted by Fast355

GM did an interesting build on one of those L99 265s to put into a 1955 Chevy back in 1995. They used the Hotcam and IIRC LT1 aluminum heads. Made about 330 HP @ 7,000 rpm. They backed it to a 4L60E with a loose converter and deep gears. Made an interesting tribute to 40 years of small block design by going back to the first small blocks 265 cid.

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Yes, Ive posted about it somewhere around here. And I just happened to have the magazine where I first saw it on the shelf next to me. November 1995 Chevy truckin page 11.
3.00 stroke crank
3.73" bore
8.8:1 compression
5.940" PM rods 10108697
ZZ4/5/6 208º/221º, 0.474"/0.510" 112º cam, the article referred to this cam as a "prototype roller cam"
single roller timing chain 14088783/roller crank gear 14088784
Cloyes steel cam and waterpump gears
LT1 alum heads
Crane H-11 tool steel single valve springs
rocker cover adapters 24502540
Vette 7 rib valve covers
Camaro 77mm MAF and elbow
HPC coated 1-.5"x 30" headers
Flowmaster mandrel bent 2-1/2" exhaust
1995 SFI PCM
lightweight PMGR LT1 starter p/n 10465293
Impala SS fuel sender and pump assy

Complete 1995 L99 evap syetem with dual cats

1990 T truck (4wd S-10) 7-5/8" rear axle
4.56 ring and pinion
Auburn limited slip 30 spline axles 3.23+ carrier
L35 high stall TC p/n 24202310

Chevy Raceshop dropped the engine in a 55 210 post car

4l60e with PCM controlled WOT shiftpoints set at 7000rpm

The engine made 329hp@6500rpm/273lb/ft torque@6000rpm

Ive always been intrigued about that engine.

peace
Hog

The 302 that I built from L99 + L31 parts for an S10 in '06 and finally installed in my Suburban in '12 is still in use and runs well enough. The Suburban it is in has rusted out and I am planning to move the engine and trans to another Suburban this spring. Details can be found here. I also have an "old school" 302 built in '94 using a 327 block, 283 crank, and a set of hypereutectic pistons from a defunct company. This engines resides in my '57 truck. Some details for this engine are here. Unlike the Suburban engine which (still) uses a stock L31 intake, the '57 engine is fed through Crossfire TBI. The 302 works hard but definitely does not have the torque that most folks like to feel in a truck. Like the DZ Camaro engines and the many, many 301 CI short track engines of old, it's a much better powerplant at higher rpm. I promise that climbing a hill at 55-65 MPH in second gear with a loaded trailer wakes up the folks in the climbing lane.

The L99 is built using a 3" stroke and a "305" bore and uses small chamber, small valve heads. L99 engines would pull heavy Caprices and Impalas along at 80mph+ on the highway and were able to sometimes deliver fuel economy in the 20 mpg range. Based on experiences with a TBI Caprice engine that a friend built using 1.6 rockers, an LT1 cam, and a modified TBI intake you could replace the L99 crank and rods with a 305 crank and rods to make a nice truck engine for light duty use.

I believe I have posted stock L99 files in the past but maybe they were not to this site. I will dig through my collection to find one. I believe you will have fun using this engine in place of the 4.3 TBI that was in your truck. And if you do the work to do a good install then you'll be ready if a deal on a "grown up" LT1 falls in your lap.

FWIW, Dynamic EFI is an advertiser here but gearhead-efi is not Dynamic EFI.

Thanks!

Lots of useful info. Thanks for your time!