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1project2many · 07-05-2017, 05:46 PM

The box pictured with the yellow connector is the DERM, the "brain" for the airbag. The yellow connector is a clue but the giveaway is the yellow tape wrapped around the harness. The PCM would be attached to the four connectors, red, blue, clear, and black, that are below the fuse box in the photos.

The CSFI systems had some problems but by this age most of the issues should be gone. We are retiring six buses this week with those fuel systems and they have from 291k to 397k miles on them. There are problems with the intake gaskets lasting over time but we've found that using the Fel-Pro perma-seal gaskets provides very good results.

A carburetor based system will not provide more power unless you change the cam. The stock CSFI intake and fuel system makes reasonable torque and is good to somewhere around 380 hp. That engine will not have a ZZ4 cam unless it was installed by a previous owner.

The steel timing chain and gears will usually last for a long time We have never changed a set in the L31 Vortec engines here. If you remove the timing cover to replace the timing set be prepared to buy a replacement. The plastic covers usually break upon removal.

07-05-2017, 05:46 PM	#17
1project2many Registered User Join Date: Mar 2012 Location: Lakes Region NH Posts: 3,158	Re: Craigslist sanity check: 4L80e + 5.7L SBC 350 The box pictured with the yellow connector is the DERM, the "brain" for the airbag. The yellow connector is a clue but the giveaway is the yellow tape wrapped around the harness. The PCM would be attached to the four connectors, red, blue, clear, and black, that are below the fuse box in the photos. The CSFI systems had some problems but by this age most of the issues should be gone. We are retiring six buses this week with those fuel systems and they have from 291k to 397k miles on them. There are problems with the intake gaskets lasting over time but we've found that using the Fel-Pro perma-seal gaskets provides very good results. A carburetor based system will not provide more power unless you change the cam. The stock CSFI intake and fuel system makes reasonable torque and is good to somewhere around 380 hp. That engine will not have a ZZ4 cam unless it was installed by a previous owner. The steel timing chain and gears will usually last for a long time We have never changed a set in the L31 Vortec engines here. If you remove the timing cover to replace the timing set be prepared to buy a replacement. The plastic covers usually break upon removal.