To LS or not to LS, that is the question

[kenh]

Well.... sacrilege or not, I'm considering dropping a LS into my 1990 C1500.

Doing a little research it looks like there will be no money savings over just rebuilding my 5.7 TBI. Yes advantages over the TBI.

I can get a 5.3 from my local pick a part for $275. Wiring harness for about $50 and ECM for $25. Then there is all the "other" stuff which I don't know about. I do know motor mounts, and possibly trans mount/cross member. Will making my instrument cluster work with the engine be an issue?

Found one internet sight that spent about $3K on a conversation on a 1990, C1500. Is this accurate? I know a lot of this will be open ended and "some" extra work.

Thanks!

Ken

 

[alpinecrick]

No TBI long blocks at a decent price?

 

[Ryanchevy1991]

Hey new member here- I recently came upon a 1998 c1500 RCSB and I’m in the process of swapping a 4.8/4L80E into it. It’s pretty involved- I would say $3,000 is pretty close cost wise. You’re gonna need to upgrade your fuel pump, and you’re 700r4 won’t work with the truck intake without some janky modifying, so you’ll want to find a complete drop out with engine and trans. I see them on Facebook marketplace for 800-1200. Also you will need to have the computer flashed- I have a guy he supplied my PCM with custom tune for $115 shipped. I think it could be done for $2,000 if you were super froogle about it

 

[Frank Enstein]

One more time!

 

[Frank Enstein]

Well.... sacrilege or not, I'm considering dropping a LS into my 1990 C1500.

Doing a little research it looks like there will be no money savings over just rebuilding my 5.7 TBI. Yes advantages over the TBI.

I can get a 5.3 from my local pick a part for $275. Wiring harness for about $50 and ECM for $25. Then there is all the "other" stuff which I don't know about. I do know motor mounts, and possibly trans mount/cross member. Will making my instrument cluster work with the engine be an issue?

Found one internet sight that spent about $3K on a conversation on a 1990, C1500. Is this accurate? I know a lot of this will be open ended and "some" extra work.

Thanks!

Ken

I will get some part numbers for you Thursday if I remember. ICT Billet makes adapters for the stock SBC mounts for like $50 And maybe !00 for a flexplate and spacer. It is easier if you get a cable drive throttle body. Much cheaper and easier.

 

[0xDEADBEEF]

Take your budget, double it, and add 50%. LOL

Honestly, it's the little stuff that just seems to bleed you dry. I'm in the middle of second LS swap, so I guess I didn't learn my lesson the first time.

 

[kenh]

I know there will be many hidden costs! Frank, thanks for the part numbers. No hurry. This project if it happens will be 9 months down the road.

Thanks!

Ken

 

[stutaeng]

My brother has a 90 C1500 and the PO swapped a JEGS crate engine. He's been using it as DD for about 2 years, and it started burning oil recently, so we've been thinking LS swap. He wants to keep his 700R4 because it was rebuilt after he bought it, but the electronics don't work with the LS stock ECU. I've told him just get a 4L60E and run that with the engine.

Anyways, $3,000+/- is probably a bare minimum budget if you do the work yourself. The little things add up quickly. Plan on truck being down for about 4-6 weeks while you work things out. Biggest thing is the guages. If you have the additional $800 or whatever for the DakotaDigital cluster, that's a really nice option, but adds a significant amount to the budget.

Best advice is get yourself the most complete (wiring harness, ECU, accessories, etc...maybe even the transmission), running engine, and drop it in. Resist the temptation to open it up. I've seen guys on YT cracking open LS engines with 150k miles and the internals look brand new.

 

[OutlawDrifter]

Stock gauges aren't that big of an issue, it's more about using the 5.7l senders in adapters and getting the wiring put together. ICT Billet sells the adapters also.

 

[Markmartin01]

I have considered this myself. I think the question for me comes down to power curve and intended use of the truck. TBI was a torque focused motor that makes good power under 4k. LS engines have outstanding heads that flow great and make killer HP but generally at a higher rpm. So are you towing a trailer or 1/4 mile? For me, we built a mild RV cam TBI 350 that'll pull a house down at 2k RPM.