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Davidf · 11-18-2021, 10:05 AM

I just finished an LS swap into my 71 Cheyenne. Yes, visit the LS Swap forums as there is a wealth of information there. I chose to go with the ubiquitous 5.3L as they are plentiful (I think mine is a 2003). At nearly 300 HP, it has plenty of get up and go...my truck is FAST with right now acceleration. Remember, our trucks are much lighter than the trucks the Vortec was intended for. And, I agree, the 4.8 is essentially the same block/architecture/platform. The only difference is stroke and pistons (flat tops on the 4.8, dished on the 5.3. Pistons are really the only way you tell the two engine apart as the block is stamped 4.8/5.3). Unless you want to really smoke the tires, why bother with a hotter cam...stock configuration is plenty quick.

A "bolt on" mechanic can do the work especially if you stay away from custom work...like building a mount to reuse the LS air filter box, etc.

Also, I used Hooker Blackheart engine stands and trans crossmember. This setup uses F body engine mounts, but buy the urethan mounts as the rubber mounts will settle over time and cause the truck oil pan to rub on the steering link. The Hooker parts positions the engine low and allows the use of the LS a/c compressor without any modifications. But, to maintain driveline angles (long bed), you need to rotate the pinion shaft down with 4 degree shims (assuming you go one piece driveshaft).

Don't buy a Painless yet. If you mechanic is any good, he will reuse the donor wiring harness and most of the C10 under hood wiring will go away anyway. I used the C10 starter circuit and lighting circuits...MOST everything else was removed.

And, I put the HP fuel pump in the stock, in cab, fuel tank (look for my thread). If you do this, it is a must to wrap the tank in sound deadening or the noise will drive you crazy.

11-18-2021, 10:05 AM	#5
Davidf Registered User Join Date: Nov 2014 Location: Austin Posts: 749	Re: Ls swap I just finished an LS swap into my 71 Cheyenne. Yes, visit the LS Swap forums as there is a wealth of information there. I chose to go with the ubiquitous 5.3L as they are plentiful (I think mine is a 2003). At nearly 300 HP, it has plenty of get up and go...my truck is FAST with right now acceleration. Remember, our trucks are much lighter than the trucks the Vortec was intended for. And, I agree, the 4.8 is essentially the same block/architecture/platform. The only difference is stroke and pistons (flat tops on the 4.8, dished on the 5.3. Pistons are really the only way you tell the two engine apart as the block is stamped 4.8/5.3). Unless you want to really smoke the tires, why bother with a hotter cam...stock configuration is plenty quick. A "bolt on" mechanic can do the work especially if you stay away from custom work...like building a mount to reuse the LS air filter box, etc. Also, I used Hooker Blackheart engine stands and trans crossmember. This setup uses F body engine mounts, but buy the urethan mounts as the rubber mounts will settle over time and cause the truck oil pan to rub on the steering link. The Hooker parts positions the engine low and allows the use of the LS a/c compressor without any modifications. But, to maintain driveline angles (long bed), you need to rotate the pinion shaft down with 4 degree shims (assuming you go one piece driveshaft). Don't buy a Painless yet. If you mechanic is any good, he will reuse the donor wiring harness and most of the C10 under hood wiring will go away anyway. I used the C10 starter circuit and lighting circuits...MOST everything else was removed. And, I put the HP fuel pump in the stock, in cab, fuel tank (look for my thread). If you do this, it is a must to wrap the tank in sound deadening or the noise will drive you crazy.