Hey guys,
I have been doing a lot of research on placing a either ls1 swap or vortec 350(96-98) into my 1986 GMC Sierra Short bed 4x4. I understand that the LS1 swap is extremely popular right now and by rights it should be. on the other hand because I will be on a budget I was wondering would it not be a little more wallet friendly and still provide fuel economy if I went with a vortec 350 96-98 swap?
I had a GMT 400 truck for about six months and it drove good. Even with it being extended cab and 4x4 it would scoot down the hwy with ease and I got 17mpg on the hwy driving 65-70. The truck was a 1997 model z71.
The vortec 350 will fit I am sure in the same location as the current engine is so I won't need knew mounts. as far as wiring in the Vortec so that I can keep the fuel injection I would use http://howellefi.com/vortec-harness-1996-0 1-5.7l-s... if I wanted to use a 4l60e or If I wanted to use a 700r4 I think I could use
http://howellefi.com/vortec-harness-1996-0 1-5.7l-s...
Now as far as the fuel system goes I know that I need electric fuel pumps that are inside the fuel tanks. My thoughts are to buy 2 new fuel tanks for a 1987 truck and then buy the sending unit and fuel pump combo that would provide the adequate fuel pressure that is needed. I'm not sure if it is that simple but in doing my research that is what I have come up with. also my debate on 4l60e or 700r4 is which one will provide me with a longer life as well as promote fuel economy. I was thinking since my truck already has a 700r4 all I would need to do is have this one rebuild and put it behind the vortec 350 and boom no driveshaft modifications to worry about the tcase will bolt up. what are yalls thoughts though? at the end of the day I just want my truck to be dependable and reliable as well as be able to move down the road when its needed. I really want to update the truck to fuel injection from carb the benefits far outweigh the cons. Thanks in advance for helping me sort this out!

 

The L31 Vortec is a good engine.. good torque and decent power. They were still in use up to 2002 in the GM Van (Express/Savana) and in the trucks and SUV's through 2000. They had anywhere between 255-350 HP. You can buy a crate version called the RamJet from GM.

I would recommend you find one complete with a 4L60E maybe even use the Transfercase from a donner and swap the whole combo in.

BC

 

If you're on a budget, have you considered an iron block version of the LS motors. You can find low mileage 5.3 (LM7) and 6.0s (LQ4), for 1/3 to 1/4 the price of the aluminum blocks.
Get a complete takeout with trans and harness, etc, you'll be way ahead of piecing together an LT1, 700R4, harness, etc

 

Around here a L31 in good used condition is hard to find. Add the cost of the updated injectors to replace the poppet style ($450), harness, etc and the cost of an LS may be cheaper. Complete drop out gets you an e-shift trans and a harness you can reuse no need to buy new.

Run, do not walk, away from anything with the Howell name on it. Their Vortec harness is setup for the 'black box' ECM which has very limited tuning support, many people with that ECM stock *swap it out* for the 0411 LS ECM. Kinda goes well with their fuel-only TBI ecm for GM motorhomes.

 

The 350 will be easier and perhaps cheaper to swap, but 4.8/5.3 takeouts are pretty cheap these days. Look for a wrecked 4.8 4x4 truck and swap everything you can.

Does anyone know if the newer axles will swap to an older pickup?