ErikwithAK01

So I found a good deal today for an aluminum block LC9-5.3L with 243 heads for $400 and I'm gonna pick it up tonight. I know the heads alone are worth that, so it is a drop in the bucket for me, but what I don't know a lot about, is the block.

What I DO KNOW, is the LC9 is an aluminum Gen-4 5.3L truck engine. What I am having a hard time finiding out, is if I can build a 400+ci stroker out of it. I have been biding my time until a good opportunity came along to pick up a cheap engine I can strip down for the block, and this might be it.

Now, I don't honestly know hardly anything about LSX stroker motors, but I DO KNOW that the extended skirts, and larger bore spacing especially are important if you want to build a 402/408, since the bore spacing on the LS1 is under 4" you can't actually house those cubes in a Gen-3 block.

I have been scouring the net, but there just doesn't seem to be many people using this block, and I think it is because it was newer, and the 5.3 was still commonly available from the previous generation for cheaper.

So here is a good question: If the bore spacing really is 4.40" then wouldn't the 243 casting heads not fit, since they were designed for the gen-3????

If I pull the 243 casting heads off this LC9, will they fit on the 2001 LS1 in my C5???

But I suppose the biggest question is...can I resleeve, or bore this block to build a budget LS3 stroker??? Will I be able to use the better square port heads???

Link to LC9 specs....
https://summitracing.custhelp.com/ap...9-engine-specs

Link to LS3 specs....
https://summitracing.custhelp.com/ap...id/4874/kw/Ls3 bore spacing

Andrew

Am also interested in what folks say. My $0.02...

No, do not believe you could get over 400 ci. Bore spacing is not your problem. On the aluminum blocks, the cylinder liner is the problem. I believe the LC9 has the same cylinder liners as the LS1, so could bore it to a stock LS1 of 3.898 or bore it a bit more, but max would be 3.905. At that bore, you could stroke it to a 4" stroke, but that would give you 383 ci. If you want to live dangerously, maybe push it to a 4.125 stroke giving you 395 ci, but that is asking for trouble. Would be better off and cheaper to get an LS2 block and put a 4.0 crank in it, giving you 402 or finding an iron block 6.0 and bore it with the 4" stroker for a 408.

TastyBacon

According to the handy table here, the max possible bore size for an LC9 is 3.908" http://www.hotrod.com/articles/max-o...for-ls-blocks/

I agree that with the aluminum block, best case, you're looking at a 383ci. That assumes that you can bore it out that far--some 5.3s have too much core shift to take the max overbore. You'll have to have it sonic checked first. No square port heads at that bore. Buying an LS2 or LS3 block makes more sense financially than re-sleeving.

The 243 heads will fit your LS1 block nicely, though

TastyBacon

The thing to do with thick-sleeved aluminum 5.3s, in my opinion, is throw boost at them!

Andrew

Yep, completely agree!

neutron82

I agree with the above, if you get a 5.3 boost it and don't mess with trying to build it up n/a... I don't think it would be safe to go over 400ci with that block either, you would be removing like a quarter inch of material to get to an ls2 stroker bore size and at that point they will probably be even thinner and weaker than ls7 sleeves... I could be wrong but it just doesn't seem feasible to me

ErikwithAK01

From what I have read continuing research, is that you have to resleeve the block if it started life as a 5.3 which is about $2100 in parts. So....I'd rather buy a brand new block for that price, and save $800.

I suppose I'll just keep my ear to the ground for a good deal on a block :/

blackmachdown

The bargains right now for aluminum block N/A builds are the l92 motors. They are basically ls3 motors that have DOD. You can find them at junkyards for $2.5k+ running with under 100k miles.