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LTX and LSXPutting LT1s, LS1s, and their variants into Third Gens is becoming more popular. This board is for those who are doing and have done the swaps so they can discuss all of their technical aspects including repairs, swap info, and performance upgrades.
I have all my goodies gathered up to build up a cheap 4.8 to put into my IROC, but after doing research, I'm a bit discontent with the power figures in comparison with other muscle cars of nowadays. Being that people are selling LQ4's for nearly 2k in my area, it's out of the question. I would like to build up a fresh engine for my resto-mod that will at least give up a good fight against the other big cars nowadays.
So, I was debating whether I should get the crank and rods from a 5.3 and make a high compression 5.3. OR Get the turning assembly from an LS1 and bore my block to build up an iron LS1.
The cam I chose for my 4.8 is a 206/212 .515"/.522" 112deg. So this cam could be used for a high compression 5.3. I also have a 98-00 LS1 cam in the garage to use if I decide to do an iron LS1.
So I'm just wondering what the best bang for the buck is here? Or should I just stick with 4.8 before I dig too deep a hole?
I'd weigh how much more you plan on doing with the car outside of the engine swap and when you'd like to be driving it. If you've got everything for the 4.8, then you're right at the point many of us were before we began to nickel and dime ourselves as we fixed things that GM did, improved them, or otherwise tried to bring these old cars up to some newer standard. This all takes time too.
My recommendation is to continue getting the swap done and the gremlins all sorted out and addressed. While you're doing that, start watching out for a good deal on another good running engine that's really the power that you want. Build it up separately from getting the thirdgen back on the road. Then you can pull the 4.8, but the bigger engine in, and know that the rest of the swap is good to go and not something you're going to be hitting snags on.
Or you could do like some of the folks around here in LS swapped BMWs, etc. and keep the 4.8 while adding a big turbo knowing that if you blow it up another one is only a few hundred bucks. All depends on your goals and how fast you want to be there.
I second everything that 3.1EyeCandy said. Use the 4.8 as a stepping stone for your next engine. I have a STOCK 4.8 in my car as a daily and it's fun compared to the 3.1 V6 it replaced. Put a cam in the 4.8, finish the swap and drive it for a while. Then get another engine and build that one and swap it later, it should only take a weekend or two the second time and you won't have much down time.
3.1EyeCandy and scooter, thanks for the input! My 86 IROC is a budget friendly resto-mod, so the entire car was torn down bare and then the engine bay and interior were painted. I still have a lot of other things to do aside from the swap, and, so, I can probably hold off to make it great the first time around. But it's great advice, I'll give it some thought.
gwarren007, thank you for the input, as well! Yeah, I've seen the LS9 cam, my only concern is that it shifts the power curve up so high. My current rear end is the stock 2.73:1, not sure if I should switch it out for a higher set, especially if I want to drive on the freeway! Lol. I also wonder how it would react with the high compression 5.3.
The ls motors were designed to rev, so in any case IMO, you need to allocate for larger gears. 3.42 or 3.73 will allow the ls motors to reach full potential.
Even with a base LO3 (305) many on this forum suggest moving to more performance gear ratio.
You make the call-
Last edited by gwarren007; Oct 11, 2020 at 10:50 PM.
That answers that! I will definitely upgrade the gear set when I swap LS1 disc brakes on the rear. I guess the LS engines are happier in a higher RPM band than the SBC's.
That answers that! I will definitely upgrade the gear set when I swap LS1 disc brakes on the rear. I guess the LS engines are happier in a higher RPM band than the SBC's.
That answers that! I will definitely upgrade the gear set when I swap LS1 disc brakes on the rear. I guess the LS engines are happier in a higher RPM band than the SBC's.
You'll spend less if you just source a 3.42 LS1 rear end which will already come with the brakes and better gear set. LS engines are more stable at RPM but they are not all fitted equally. The 4.8 is still fitted with truck parts designed to make its power at a lower RPM. A cam and spring kit goes a long way to increasing the usable RPM range of the motor but it can start to domino from there. As others have mentioned, I would get the engine to run and build something on the side. The engine is often the easier part of the swap. It is everything else that cots money. Turning a 4.8 into a 5.3 or 5.7 is a waste of money. You'll still have an engine with less potential than an 6.0+, and likely spend more building it.
Last edited by ShiftyCapone; Oct 12, 2020 at 08:03 AM.
You'll spend less if you just source a 3.42 LS1 rear end which will already come with the brakes and better gear set. LS engines are more stable at RPM but they are not all fitted equally. The 4.8 is still fitted with truck parts designed to make its power at a lower RPM. A cam and spring kit goes a long way to increasing the usable RPM range of the motor but it can start to domino from there. As others have mentioned, I would get the engine to run and build something on the side. The engine is often the easier part of the swap. It is everything else that cots money. Turning a 4.8 into a 5.3 or 5.7 is a waste of money. You'll still have an engine with less potential than an 6.0+, and likely spend more building it.
Shifty, I had already gone around scavenging for all the brake parts off a fourth gen last year. I have everything already, including the cables and lines. So maybe I should go find a 3.42 rear and just leave the brakes at the scrapyard? How common are the 3.42's? Did the V6 cars have them?
Also, that's probably the truth of that matter. Power costs money, and it would be a waste to build up a 5.3 or 5.7 out of my 4.8.
Going off of that, if I want upgrade-ability for the future, should I swap a more capable fuel pump into my plastic tank that I plan to put into the car? And there's the transmission. I have a 4l60e out of an LS1 Camaro that I still need to rebuild. I've heard that 6.0's are better matched with the 80e. Would it be best to swap an 80e in when I swap in a larger engine? It would obviously require switching some pins around in the main trans connector and some tuning.
Thanks again for the help, guys. I really appreciate it!
