Might have bought a 5.3 "LS1"....HELP

[SiskMan]

I was tinkering today and noticed that my cylinder heads say 706 on them. So now im trying to find the block number to run that and see if I just bought a 5.3 WS6...... The trans tunnel has scratches and dings from what is probably an engine/trans pull. Where do I look for the number on the block itself?

[pajeff02]

It's tough to see -- back of the engine, driver side, below the head. You will need a telescoping mirror and a flashlight.

[SMWS6TA]

wow that would piss me off.

[SiskMan]

The door stickers and everything else check out fine. its a true ws6. has everything that it should, ls1 intake, power steering cooler, etc. That doesn't mean anything tho i guess since the short/long blocks are interchangeable.

[SMWS6TA]

did you get it from a private seller or a dealer?

[SiskMan]

private seller. it was pouring ass rain when I bought it and needless to say I missed a few things. This is my first LS car and I really didnt know what to look for. The car is most definitely fast and has no problem at all getting to 120 (fastest ive gone). I really hope the block number gives me some good news when I get a peak back there.

[KahanaReef]

I wonder if the previous owner had one of the stock heads crack or something and had easy access to a set of 706 heads lying around.

Hopefully your block belongs to your car and it's just the heads. It's not that big of a deal, and easily remedied, but the seller should have let you know. Was the seller the original owner of the car?

[SiskMan]

I wonder if the previous owner had one of the stock heads crack or something and had easy access to a set of 706 heads lying around.

Hopefully your block belongs to your car and it's just the heads. It's not that big of a deal, and easily remedied, but the seller should have let you know. Was the seller the original owner of the car?

No, just some middle aged dude who had bought it for his mid life crisis. You could tell he really didn't know much about cars. damn i really hope its just the heads since I could live with that. They would at least give a bump in compression. Ill let you guys know after I get off work. PRAY TO THE CAR GODS FOR ME!!! lol

[KahanaReef]

No, just some middle aged dude who had bought it for his mid life crisis. You could tell he really didn't know much about cars. damn i really hope its just the heads since I could live with that. They would at least give a bump in compression. Ill let you guys know after I get off work. PRAY TO THE CAR GODS FOR ME!!! lol

Well, he apparently knew nothing about it then. I have a hard time believing that anyone would do an LS1 to 5.3 swap in an fbody. But there are some strange people in this world...

[SMWS6TA]

KR it's a very common swap when you can't find or afford a LS1/6 block. Plus the turbo guys love the 5.3 blocks.

[98TransAmWs-6]

KR it's a very common swap when you can't find or afford a LS1/6 block. Plus the turbo guys love the 5.3 blocks.

This....I hear and see about it all the time with turbo guys as well as the 4.8.

[SiskMan]

Stuck a magnet to the block this morning so things aren't looking good. Haven't looked at the casting number though yet. COME ON LQ4!!!!

[KahanaReef]

KR it's a very common swap when you can't find or afford a LS1/6 block. Plus the turbo guys love the 5.3 blocks.

I suppose if money is that limited. I guess its just not something I would ever consider doing myself

[35th-ANV-SS]

To expand further, the 5.3L blocks are iron whereas the LS1 block is aluminum. While the LS1/LS6 will make more power, the iron block will hold a lot more power when boosted. This is why Scott is saying turbo guys like that block over the LS1.

Plus, it's generally cheaper to buy.

[SiskMan]

Makes me pretty angry. I've always wanted a ws6 and I worked my ass off, saved up forever, and waited patiently until I found a car that was just right. An now I have a car with the wrong engine that I shelled out serious cash for.

[SMWS6TA]

To expand further, the 5.3L blocks are iron whereas the LS1 block is aluminum. While the LS1/LS6 will make more power, the iron block will hold a lot more power when boosted. This is why Scott is saying turbo guys like that block over the LS1.

Plus, it's generally cheaper to buy.

[KahanaReef]

To expand further, the 5.3L blocks are iron whereas the LS1 block is aluminum. While the LS1/LS6 will make more power, the iron block will hold a lot more power when boosted. This is why Scott is saying turbo guys like that block over the LS1.

Plus, it's generally cheaper to buy.

That does make more sense to me. I just think back to when I was doing the rebuild for my Chevelle, and even in my less patient mid 20's, I opted to wait the extra almost two weeks to get my original block back because I wanted to retain my matching numbers.

[98TransAmWs-6]

Makes me pretty angry. I've always wanted a ws6 and I worked my ass off, saved up forever, and waited patiently until I found a car that was just right. An now I have a car with the wrong engine that I shelled out serious cash for.

It will say what liter block it is near or behind the water pump so you 100% certain.

[kingls1]

To expand further, the 5.3L blocks are iron whereas the LS1 block is aluminum. While the LS1/LS6 will make more power, the iron block will hold a lot more power when boosted. This is why Scott is saying turbo guys like that block over the LS1.

Plus, it's generally cheaper to buy.

I would think It would be pretty easy to tell a aluminum block to a steel one. I think I would have come back when the rain was over.
However Hot Rod did a test maybe a year ago where they took a junk yard truck motor (thought it was a 5.3 turned out to be 4.8) bolted a Fast 102 and threw it on the dyno, 404hp then came twin 76mm turbos @ 8psi was 800+hp. The test ended at 26psi and 1,200+hp after 60 dyno pulls. The test was to see how much it would take before blowing and that did not happen. So maybe a turbo or procharger is in your future.

[SMWS6TA]

It will say what liter block it is near or behind the water pump so you 100% certain.

on the drivers side below the cylinder head.