4th gen 5.3 vs 5.7
Thread Starter
Launching!
Joined: Feb 2014
Posts: 206
Likes: 4
4th gen 5.3 vs 5.7 I'm going to put an LS in my 71 Cutlass convertible. Right now I have a complete with everything, harness, accessories, ecm, pedal, bcm, tcm, etc. 2006 5.3 from a Rainier. It had a DOD lifter fail. I was planning on putting in a cam and get rid of the DOD and milling the 243 heads for better compression. I have the opportunity to get a cheap running 2001 5.7 with accessories, no harness. I'd want to swap the cam and probably use the intake from the Rainier. I am leaning towards the 5.3 because I have everything I need and it was only $250, but the larger 5.7 is appealing.
How much difference in power could I expect between the two, both with a cam, headers and using the Rainier intake? I've got an extra set of 243 heads I could use on the 5.7 if that would help.
Thanks
How much difference in power could I expect between the two, both with a cam, headers and using the Rainier intake? I've got an extra set of 243 heads I could use on the 5.7 if that would help.
Thanks
TECH Addict
Joined: Aug 2005
Posts: 2,305
Likes: 126
From: Monroe,NY
I would use the 5.7 and put the 243 heads. Not sure what cam the rainier has but you put a LS6 cam and 243 heads and you basically have a 2004 ZO6 motor 405 hp. Plus the 5.7 will have more torque which you will need in that big cutlass.
10% power difference across the board, with lower power band which as mentioned above, better for the heavier car. I agree that the 5.7 will be better in the end. Even save you a hundred pounds with the aluminum block. With milled 243s, you could get to almost 11:1 compression ratio since the LS1 starts out with 10:1.
Now the caveats..
That 2006 engine is most likely 58x crank reluctor and 4x front cam sensor. So matching PCM and harness. The LS1(5.7) is going to be 24x and rear cam sensor. The cam sensor can be addressed by using the 5.3 front cover, sensor, timing set. The reluctor is a different story. Lingenfelter sells a box for about $300 that converts the signal from 58x to 24x but you need the opposite for this...
So I think you have these options:
Get an earlier harness for about $150.
Pay someone to put a 58x reluctor on the 5.7 crank.
Use the 58x 5.3 crank with the 5.7 rods and pistons in the 5.7 block but you would have to get the assembly balanced to run right.
Bore the 5.3 to 5.7(most are capable) and use the LS1 pistons in the 5.3. Still balancing required at least.
There may be other tricks to making a 24x engine work with a 58x setup but I am not familiar.
Now the caveats..
That 2006 engine is most likely 58x crank reluctor and 4x front cam sensor. So matching PCM and harness. The LS1(5.7) is going to be 24x and rear cam sensor. The cam sensor can be addressed by using the 5.3 front cover, sensor, timing set. The reluctor is a different story. Lingenfelter sells a box for about $300 that converts the signal from 58x to 24x but you need the opposite for this...
So I think you have these options:
Get an earlier harness for about $150.
Pay someone to put a 58x reluctor on the 5.7 crank.
Use the 58x 5.3 crank with the 5.7 rods and pistons in the 5.7 block but you would have to get the assembly balanced to run right.
Bore the 5.3 to 5.7(most are capable) and use the LS1 pistons in the 5.3. Still balancing required at least.
There may be other tricks to making a 24x engine work with a 58x setup but I am not familiar.
Thread Starter
Launching!
Joined: Feb 2014
Posts: 206
Likes: 4
10% power difference across the board, with lower power band which as mentioned above, better for the heavier car. I agree that the 5.7 will be better in the end. Even save you a hundred pounds with the aluminum block. With milled 243s, you could get to almost 11:1 compression ratio since the LS1 starts out with 10:1.
Now the caveats..
That 2006 engine is most likely 58x crank reluctor and 4x front cam sensor. So matching PCM and harness. The LS1(5.7) is going to be 24x and rear cam sensor. The cam sensor can be addressed by using the 5.3 front cover, sensor, timing set. The reluctor is a different story. Lingenfelter sells a box for about $300 that converts the signal from 58x to 24x but you need the opposite for this...
So I think you have these options:
Get an earlier harness for about $150.
Pay someone to put a 58x reluctor on the 5.7 crank.
Use the 58x 5.3 crank with the 5.7 rods and pistons in the 5.7 block but you would have to get the assembly balanced to run right.
Bore the 5.3 to 5.7(most are capable) and use the LS1 pistons in the 5.3. Still balancing required at least.
There may be other tricks to making a 24x engine work with a 58x setup but I am not familiar.
Now the caveats..
That 2006 engine is most likely 58x crank reluctor and 4x front cam sensor. So matching PCM and harness. The LS1(5.7) is going to be 24x and rear cam sensor. The cam sensor can be addressed by using the 5.3 front cover, sensor, timing set. The reluctor is a different story. Lingenfelter sells a box for about $300 that converts the signal from 58x to 24x but you need the opposite for this...
So I think you have these options:
Get an earlier harness for about $150.
Pay someone to put a 58x reluctor on the 5.7 crank.
Use the 58x 5.3 crank with the 5.7 rods and pistons in the 5.7 block but you would have to get the assembly balanced to run right.
Bore the 5.3 to 5.7(most are capable) and use the LS1 pistons in the 5.3. Still balancing required at least.
There may be other tricks to making a 24x engine work with a 58x setup but I am not familiar.
I agree. An aluminum 5.3 in good shape with all supporting bits is worth some cash for sure. Probably enough to get your 5.7 going and still have a little left over.
