Want to build 5.3/LM7 as 5.7 truck/towing engine
09-21-2018, 08:54 PM
#1
Want to build 5.3/LM7 as 5.7 truck/towing engine Hi folks!
I live up in Alaska and am building a 1987 Jeep J20 to tow my 1997 Jeep Cherokee XJ. The J20 is a 3/4 ton truck with a lame AMC 360 that I am not a fan of. A friend has a 5.3 LM7 for $500 I plan to purchase. I'd like to cheaply build a mildly modded LS for my truck/towing application. I've done some research and reading. I'm familiar with engines and LS's in general. I built a very high strung Jeep I6 stroker for the "Race Jeep" that runs 11.3:1 CR and a custom Lunati Solid cam. I want to be able to tow it to some wheeling locations and races.
I'd like to bore the iron block out to 3.898 (which is about all the local and only machinist can do for me) for the added CI to help make TQ and move the TQ curve down. I plan to run bone stock 862 heads and an upgraded cam. Can I easily make 400+ lb ft of torque?
Engine will either be backed by an NV4500/241 or a 4L80E and 241. I'm really starting to lean toward the 4L80E (out of a 1992 or 93 K2500 friends and I have laying around).
My goals are fairly reasonable fuel mileage and torque. Not running a 6.0 because I'm trying to do this "cheaply" and I have a 5.3 for a decent price available and most things are quite expensive when you live on an island in Alaska. If my goal was to just go out and buy an engine based solely on making a mountain of torque it would be a different conversation. But the engine at hand will make more than enough power I believe.
Also, it will be carb'd
I live up in Alaska and am building a 1987 Jeep J20 to tow my 1997 Jeep Cherokee XJ. The J20 is a 3/4 ton truck with a lame AMC 360 that I am not a fan of. A friend has a 5.3 LM7 for $500 I plan to purchase. I'd like to cheaply build a mildly modded LS for my truck/towing application. I've done some research and reading. I'm familiar with engines and LS's in general. I built a very high strung Jeep I6 stroker for the "Race Jeep" that runs 11.3:1 CR and a custom Lunati Solid cam. I want to be able to tow it to some wheeling locations and races.
I'd like to bore the iron block out to 3.898 (which is about all the local and only machinist can do for me) for the added CI to help make TQ and move the TQ curve down. I plan to run bone stock 862 heads and an upgraded cam. Can I easily make 400+ lb ft of torque?
Engine will either be backed by an NV4500/241 or a 4L80E and 241. I'm really starting to lean toward the 4L80E (out of a 1992 or 93 K2500 friends and I have laying around).
My goals are fairly reasonable fuel mileage and torque. Not running a 6.0 because I'm trying to do this "cheaply" and I have a 5.3 for a decent price available and most things are quite expensive when you live on an island in Alaska. If my goal was to just go out and buy an engine based solely on making a mountain of torque it would be a different conversation. But the engine at hand will make more than enough power I believe.
Also, it will be carb'd
Last edited by JeepManiac; 09-21-2018 at 09:54 PM.
