I have everything here to build an iron ls1. It would be a stock internal build with a 5.3 block bored .118 over. Debating if I build it and slap my twins on it or just find a good block for my gen 4 rotating assembly. About the same either way I go as far as price to build. I won't be buying any crank rods pistons either way.

 

A 5.3 bored .118 over? Is that a typo?

 

I didnt know that you could bore a 5.3 to a 5.7. But it makes sense.

 

If I had a choice, I would stick with the gen 4 rotating assembly.

 

I'd rather use the gen 4 stuff. Looking about the same price for a good block Vs what I need to finish the ls1 clone.

 

Unless you want to break it I'd go with the G4 internals and if your not using the G4 crank have it re=balanced. From my research you can go to 800 rwhp on the G4 internals with no concerns as long as you gap the rings properly for the intended boost and tune it. Good Luck! JD

 

Not a good idea at all. Boring it that much will only weaken the cyl walls. Leave the bores alone and it will be much happier. Untouched gen4 is the way to go IMO.

 

The .118 over bore is quite common, and a local shop here builds quite a few as turbo motors, and claims no issues... I have a buddy that just had one sonic tested, and bored, i'll see if I can get the results.

 

You won't have a comfortable amount of meat between the cyls with a .118 bore for big power. Sure people do it, but it's not a good idea IMO. A shop worth a darn that builds turbo engines would know that. Let us know what the sonic test results are on a .118 bore 5.3.

Untouched boosted 6.0's are cracking regularly and commonly have cyls in the .130-.150 range… add a .030-.040 to that and the walls are getting too thin. After taking .118 out of a 5.3 there's not a comfortable amount of material left. We had around .100 on some cyls when taking a 5.3 out to 4" bore. No way I'd be comfortable throwing boost at that... Better off with thicker cylinder walls and more boost than vise-versa.

 

.100 on a 4"bore puts you at .150 on a 3.900 bore which is better than some before the bore. I'm not saying its a great idea, but for those wanting a better selection of pistons its a viable option vs a 6.0. Back in the day we'd consider anything with a .140+ after a bore a suitable block, and .120 on your everyday rebuild.

 

Talked to my buddy, and his 01 5.3 had .160 or better after the .118 bore. Not sure if that is a typical number, but I personally wouldn't be afraid of it for most turbo builds.

 

I still don't understand why you would want to? Not like you'll get a night/day power gain. I'd add boost instead of farting around with an overbore and weakening the integrity of the block. It's not worth the cost/effort. HP per $ spent just isn't there.

 

I agree (tried to talk my buddy out of doing anything to it), but some just don't do jy builds, want good parts, and off the shelf ls1 stuff is easier to find . That's why they build theirs, and we build ours...

 

If I didn't need a block for the gen 4 stuff this wouldn't have even been considered. As much as driving over the crank sounds like a fun idea I'm gonna wait and buy a block. I'll use the iron ls1 elsewhere at a later date. .160 isn't bad for a wall thickness but .250 sounds a lot better

 

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As fun as that could be I'd rather not spit the crank out the bottom. I'm gonna go ahead and send the block out and have it bored. Since its a cheap build at this point I'll just use it to get the car going until I find a good 5.3 block.

 

Nothing wrong with cheap and easy! Try those hyper speedpro pistons out for us! Should be every bit as strong as an OEM gen4 piston if notmore. They have more meat above the top ring land. Super cheap to boot. I was tempted to buy a set last go around but a gen4 rotating assy fell into my hands for $100. Believe they were like around $200 last I looked

 

I saw where you sai drive over the crank and it reminded me of that picture. Good stuff.

 

I thought the GEN 3 rotators where good at holding 700-750ish whp.
I would just roll with the JY stuff. Anything after that is just spent money. Unless your going big HP and class racing dont bother.

 

There is no magic RWHP number that a gen3 is 'good to'. Vehicle weight, gearing, and torque @ 'X' RPM are the big contributors.

Assuming no detonation and the tune is spot on....

Most make too much power too early in the RPM band and this bends the rods. IMO you can take a gen3 up pretty high in the power range (800ish) if you keep the power under 500whp or so till 5k, then pour the power on in the upper RPM. Some guys are making 700+ ftlb at 4000 rpm. Then add a heavy chassis and long gearing and you can see why the rods give.