help me id my motor
03-30-2015, 07:47 PM
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help me id my motor Hi guys,new to the LSX world and just bought my first LS motor out of a 2012 chevy van im told.The only id I could find is AW7 and heads that are 799 is this a 5.3?or 6.0?Im building a big mud truck and am torn between useing this motor or a cummins 5.9 and allison I already have.Talk to me about why I should use this vs the diesel,and I was thinking a th400 trans less electrical the better in the mud.Thanks guys Earl.
03-31-2015, 06:25 PM
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Looked behind the flex plate and saw 4.8/5.3 so I guess its a 5.3?# on block are 12576177 do they mean anything?I bought this without a computer so now I have to decide what is best to go MSD 6010 box and carb or can you guys recomend a standalone system that is kinda plug and play as im not very good with electronics.Also which would play better in the mud?Looking for about 400 ft # torque what mods should I do cam, headers,tune?Thanks Earl
04-04-2015, 11:58 AM
#4
How BIG of a mud truck are we talking? And are you mid /riding/ or mud /racing/?
If I were building a BIG truck I'd go with that Cummins. A 4.8/5.3 can be made to run very well but I think you'd need a positive-displacement type of supercharger(also available but not exactly cheap) to get the grunt you need to push a big truck and turn some big tires. 6.0 or larger maybe but it's basically the same thing and about 14% more of it. The Cummins is a whole different ball game. It, properly built, will produce that torque 3000RPM lower and that is no joke. From my experience, a vehicle in the mud will act like it weight 2x or more than what it does on the street..so you almost have to build the drive train as if you have that heavy of a truck.
If I were building a BIG truck I'd go with that Cummins. A 4.8/5.3 can be made to run very well but I think you'd need a positive-displacement type of supercharger(also available but not exactly cheap) to get the grunt you need to push a big truck and turn some big tires. 6.0 or larger maybe but it's basically the same thing and about 14% more of it. The Cummins is a whole different ball game. It, properly built, will produce that torque 3000RPM lower and that is no joke. From my experience, a vehicle in the mud will act like it weight 2x or more than what it does on the street..so you almost have to build the drive train as if you have that heavy of a truck.
04-04-2015, 06:06 PM
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how big? First off this will be a buggy build but in a mega truck size.I already bought a set of axletech 4000 rears one front and one rear and just won another set on government liquiation for a set of two steering axles,so now it will have 4 wheel steer.Not sure on tire size just yet but will probably be either 23.1 x26 (66" tall) or 23.1 x34 (73" tall) rice and cane tires.Im going to use a SCS fulltime 4x4 transfer case with about 4.0 - 1 gearing or more as I only want top speed to be about 30 MPH.This will be a slow going rig not one of those ***** to the wall high HP rigs,just something different to cruise around the mud bog shows/events.I picked up a rebuilt 6bt and allison at545 on craigslist that I thought I was going to use but found out that trans is only good for about 450 ft # of input torque and would need to swap in a mt 654 or larger allison to handle any more torque reliably.That trans and bellhousing would add up quite qwik.So I thought that if I could use the LS motor and get about 400ft # at say 6000 rpm it would equal 800ft# at 3000rpm of the diesel and save a lot of weight(6bt=1100# allison 654=650#total of 1750# vs about 650# for 5.3 and th400)A 1000# saveings is quite a bit to not have to carry through the mud.I thought long and hard about the diesel and just think that the weight and the piping of running the intercooler to the rear to protect it from mud would get to involved.The radiator will be rear mounted either way.So I think for now unless someone can tell me otherwise im sticking with the 5.3 though I wish it was a 6.0,and maybe ill through a turbo on it to get a little more torque,but first I have to school myself on these motors as im an old school BBC guy.I have a Shaforff 540 BBC sitting in a cobra replica I started years ago but never finished that could go in,but if I take that motor out ill never finish it.Well thanks for listening and please let me know your thoughts thanks Earl
04-04-2015, 10:56 PM
#7
Keep in mind also that an iron-block 5.3 can be bored right out to stock LS1(5.7) bore. You can find some cheap used 5.7 pistons, new rings, and you've got yourself a 5.7. You would also gain compression and that's power accross the whole powerband. I am thinking LS1 pistons with 5.3 heads would get you almost 10.5:1. But that's based on what I had planned with my 2000-ish 5.3(LM7). You will need to check max bore on your late model engine.
Have you figured out that it is def a 5.3 and not a 4.8? The only difference is stroke. Also if you are concerned with weight, there is a 50K mile LS2 short lock which would do wonders with your 799(243) heads for sale in the parts section right now for $1500. That's aluminum 6.0. 400/400 factory rating with all the smog, cats, etc...and I consider it underrated.
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04-04-2015, 11:10 PM
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No I havent found out if its a 4.8 or 5.3 for sure.When I bought it ,it was still attached to the frame that was a 8 bolt wheel dually setup so I thought it was a 3/4 or 1 ton and was hoping it was a 6.0 but I guess not.Ill be at my shop tomorrw is there anything I can look for to help id it?Origanally I was going to use the 540 but came across this motor for a good price so bought this and am kinda disappointed that it may be a 5.3 or worse yet a 4.8.I guess thats what happens when I make spur of the moment desitions without doing my homework first same goes for buying the diesel.So now I just need to figure out what to do and sell off the diesel to fund the LS to put it in either the buggy or the cobra.
04-05-2015, 12:10 AM
#9
Your casting number, 12576177, doesn't tell us anything more than the 5.3/4.8 since it's the same block but different rotating assembly between 4.8 and 5.3. There should be some additional numbers either on a sticker somewhere around the engine or better yet laser-etched into a flat, machined surface of the block that should tell us something more. Any numbers could tell us something so just keep looking. Any way to get the VIN of the vehicle it came out of? Did you get the PCM?
You could just pop the oil pan off and measure how far up/down the piston goes. 5.3 is like 92mm and 4.8 is like 83mm. Check to be sure if you go that route but 5.3 is def longer stroke than 4.8.
Where are you located? I have a neighbor looking for a Cummins setup.
You could just pop the oil pan off and measure how far up/down the piston goes. 5.3 is like 92mm and 4.8 is like 83mm. Check to be sure if you go that route but 5.3 is def longer stroke than 4.8.
Where are you located? I have a neighbor looking for a Cummins setup.
Last edited by Mercier; 04-05-2015 at 12:31 AM.
04-05-2015, 07:15 PM
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Mercier im in south jersey and im sorry but my brother already called dibs on the 6bt for a ****** rat rod hes building.I checked out that 6.0 in the classifieds and its tempting but will have to wait for some funds from my brother for the diesel before I spend anymore money.Went to the shop today and the only numbers I could find are "AW7" on a few stickers does this mean anything?
