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I've searched around a bit and only come across one thread similar to the info Im looking for. I picked up a clapped out LQ4 for cheap and gutted it, had it punched out to 4.065 and installed factory LS3 pistons and rods and had the stock LQ4 crank cleaned up. Going to be replacing the LQ9 thats currently in my 01 SS with the new motor (LQ9 spun a cam bearing). I already have a set of 243 heads on the shelf, and an ls6 intake thats on the car now, along with a Tick Polluter V2 cam and factory LS3 head gaskets. Not going to mill the heads so I dont run into any PTV issues with the flat top LS3 pistons but plan on getting them cleaned up and a good valve job since theyre used. Now I am starting to wonder if I should part ways with the 243s, LS6 intake and Polluter cam and go with an LS3 style top end as well. Car is a 6 speed with factory 3.42s for now but the rear is need of a rebuild anyway so I will most likely end up going with 4.10s when that happens. Might see a drag strip a few times a year but mostly will be street driving and occasional commutes to work (about 40 miles one way). Also running 1-7/8" headers with custom ory and a 4" exhaust dumped at the rear bumper. Im pretty set on keeping everything I currently have, but have been wondering if the LS3 top end with a properly specced cam would work better for my needs. Looking forward to hearing what people smarter than myself have to say on the matter and thanks in advance!
I would sell the 243's & LS6 intake, and short block together, and dismiss the LS3 top end idea simply because at this point you're at the price of a nice L92 engine.... install the cam into that L92 engine, pick up a nice LS3 intake for the cheap and you're having lots of fun and 80lbs lighter.
I dont want to mess with going from 24x to 58x, removing DOD/AFM if necessary, and on top of all of that trying to sell what I already have and find a decent low mileage motor in my area for a reasonable price. I know I could stumble across a decent deal if I waited long enough but the hassle of trying to buy a new motor and sell everything I have now just seems like a waste after the time and money ive put into this motor already. I appreciate the input though.
The LS3 va rectangle port debate has been beaten to death. Everyone seems to have a different opinion.
I agree, it has been beaten over and over again. But the main stuff I see on it is either guys wanting to put rectangle port heads on trucks that were originally cathedral headed or bored/stroked combos going for all out HP. I only found one thread that was trying to decide whether to run cathedral (specificaly 243s) or rectangle heads on an iron block 6.2 build, but the information stopped long before any of it was very useful. I want this car to make a good bit of power, but Im willing to sacrifice an all out number for drivability/reliability.
I agree, it has been beaten over and over again. But the main stuff I see on it is either guys wanting to put rectangle port heads on trucks that were originally cathedral headed or bored/stroked combos going for all out HP. I only found one thread that was trying to decide whether to run cathedral (specificaly 243s) or rectangle heads on an iron block 6.2 build, but the information stopped long before any of it was very useful. I want this car to make a good bit of power, but Im willing to sacrifice an all out number for drivability/reliability.
Driver-ability/reliability? Then - keep the Cathedral, have them ported have someone spec you out a vicious mid range cam. And enjoy your stout 6.2 liter engine. It's going to haul *** & groceries!
I wonder what it would take for me to convince KCS to take my 243 heads under his wing and work them over. Ive gone through your build thread more than once and the machine work and attention to detail you put into things is second to none.
what ever happened with this? I'm doing the same thing but with 823 rectangle port heads and an L92 intake. trying to figure out what piston-to-wall clearance people have used since these pistons actually spec out at around 4.0665 instead of just 4.0650. my machinist and I were thinking go to like 4.0670 or 4.0675 for some clearance, but our concern is that we don't want to go too large, then have piston slap when the coating wears off. any ideas?
Last edited by Helomedic1171; Jul 2, 2017 at 09:45 AM.
I think I set mine somewhere around .0015"-.0020", no piston slap issues. Skirts all looked good when I tore it down, except for the cylinder that dropped the valve.
I think I set mine somewhere around .0015"-.0020", no piston slap issues. Skirts all looked good when I tore it down, except for the cylinder that dropped the valve.
what ever happened with this? I'm doing the same thing but with 823 rectangle port heads and an L92 intake. trying to figure out what piston-to-wall clearance people have used cine these pistons actually spec out at around 4.0665 instead of just 4.0650. my machinist and I were thinking go to like 4.0670 or 4.0675 for some clearance, but our concern is that we don't want to go too large, then have piston slap when the coating wears off. any ideas?
4.070" is the first oversize and can be achieved by just honing the block, preferably with a torque plate. For piston to wall clearance use the piston manufacture's recommendation.
4.070" is the first oversize and can be achieved by just honing the block, preferably with a torque plate. For piston to wall clearance use the piston manufacture's recommendation.
64post, I don't think you understand what I'm asking.
I'm using a 6.0 block, bored 4.065, using L92 pistons. the pistons came in a box, direct from Mahle, and have none of the clearance/bore size information on the label on the box. also, they normally have clearance etched into the top of the piston (in the case of OE replacement pistons). these do not have the "spo" number (Mahle rep says this is "german for clearance") etched into them, and therefore have no such manufacturer's recommendation. In addition, any clearance spec'd would be for that piston in an aluminum block, since that was the OE application, and Mahle does not have specs for putting said piston in an iron block since GM never did it either.
That said, Thanks for your insight, KCS, that's where I was thinking we should be. usually factory clearance is .0007 for LS1 and LS2 pistons, so we were thinking add .001 for a total piston-to-wall clearance of .0017 which is dead in the middle of what you used. thanks for the reply.
If anyone else has any input, feel free to add it.
If it's clapped out why are you splitting hairs? Why not just step up to the first oversized for Ls3? Never mind, I see you're not the op.
No, I was trying to use the search feature before I post a new thread. I don't post much, but I've lurked in this forum and been a member long enough to know that you get more help when you try to find the answers first.
The block in question is a 6.0 block my machinist has, it needed to go 4.056 before it cleaned up the scratched cylinder. I went ahead and got new pistons since 3 of the ones I had were questionable. The idea is to build a stout 6.2 in an iron block so the client can pull a trailer or haul whatever to his heart's content without any structural issues. The truck is a former tractor pull truck and I'm concerned it may rip the main webs apart when the chassis flexes under load.
Last edited by Helomedic1171; Jul 8, 2017 at 10:48 AM.
Bringing this back from the dead for some results, finally. Got the car back together and running and put her on the dyno this morning. She made 438/437 on a DynoJet dyno. Just as a refresher the car has an iron block 6.0 punched out with LS3 rods and pistons, stock crank, factory 243 heads with .660" springs, 239/244 .635”/.610” LSA112+3 Tick Polluter V2 cam factory ls6 intake, 42# injectors, 1-7/8" long tubes, 4" exhaust all the way out the back. I was HOPING for 450+ to the tire, but I feel like the heads and intake are holding me back. All in all the car runs and drives great and has a ton more power than the unknown cammed 6.0L that was in it when I bought it.
With an LS3 top end (heads and intake) I would bet you'd be around at least 470 and if your intake (lid/tube) setup is good and the exhaust is good it'll probably do closer to 490
Bolt on and cam only LS3's do near 500 rwhp, you should be able do the same especially being that it's a stick car.
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