blue by you

iTrader: (5)

I will be building a 370 LQ4 when I get home in 2010 from Iraq and have a question. I have heard from many vendors that when you run L92 heads on a LS engine, you have to have specific pistons to clear the big L92 valves. But I've read about quite a few people that have run off the shelf pistons and not had a problem with clearance at all. So anyone that has built a 370/L92 heads/L76 intake, please chime in and help me out.

briannutter

The L92's pose a problem IF the cam is sizeable enough. I do not not the cam duration threshold of when you'll start to run into problems. The LS1,2 stuff used to be at about 228@.050 before pockets were necessary.

Sales2@Texas-speed

iTrader: (5)

Wiseco and Diamond both offer shelf stock pistons setup for the L92/LS3 valves. Wiseco keeps more of these in stock than Diamond so wait time will typically be less if you decide to go Wiseco. We can get you either company's pistons quickly and at competitive pricing.

With a stock, flat-top, GM piston in the 6.0L you'd be limited to about a 228º@.050" intake duration without a valve relief. Now with the valve relief offered by both Wiseco and Diamond, you'll be able to run quite a bit larger duration without clearance issues if that's what your goal is for your combo.

Let us know if we can help! We stock a wise variety of pistons from Wiseco and Diamond for the 370 and can help answering any questions you might have about your build

gayslowassNALSjunk

iTrader: (2)

+1 for the Diamonds. They are very nice.

blue by you

iTrader: (5)

Matt, can you PM me a price on those pistons (Diamond and Wiseco) from you and I will get with you when I get back from Iraq in 2010. Thanks, Jess

Sales2@Texas-speed

iTrader: (5)

Do you know what kind of relief you want/need? There are quite a few options to get the compression you want. Any idea? What head are you going to run and what compression are you wanting?

blue by you

iTrader: (5)

Not sure on the relief I will need. I will be running an L92 head, stock crank, whatever rods needed to match up with the pistons. I would like to be around 10.5 CR and I do plan on having the heads milled some to get the compression around there. What do you have in mind?

68 RS Convertible

iTrader: (1)

I built a .030 6.0, 370 CID and am running Mahle flat top pistons with L 92's that were milled .025. Factory GM MLS head gaskets which I believe are .051 thousands. These pistions had valve already cut into them. I just put some clay in there turned the engine over so both intake and exhaust valves opened and closed. I didn't measure, but it didn't hit, seemed to have plenty of clearance. I'm running a TSP 333/339 .595/.603 cam.

blue by you

iTrader: (5)

What was the Mahle part number if you don't mind me asking? Otherwise I was looking on Wiseco's website and found part number K398X3. It says they will fit L92 heads.

68 RS Convertible

iTrader: (1)

I got these through Lingenfelter P/N LS1314030F04