LM7 with flat top pistons
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From: Ottawa, KS
Car: 1991 Camaro RS
Engine: 305 TBI
Transmission: 700R4
Axle/Gears: 2.73
LM7 with flat top pistons
I am building a LM7 and I have it torn all the way down and now im ready to rebuild. I am wondering if I could put flat top pistons in and not have a problem with piston to valve clearance. Im thinking 4.8 pistons. Do i need valve reliefs? This is the cam I am running http://www.summitracing.com/parts/cca-54-600-11 . Also I have 706 heads. Thanks
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From: Marietta, GA
Car: 92 Z28
Engine: LS1
Transmission: T56
Axle/Gears: 3.73 10 bolt
Re: LM7 with flat top pistons
Only one way to know for sure. Doesn't look like that cam has a huge lift so you might be alright.
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From: Milwaukee
Car: 92 Firebird, 77 Trans Am SE, 86 Z28
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Axle/Gears: 3.08 posi, 3.23 posi, 3.23
Re: LM7 with flat top pistons
I'm no LSx expert but I believe the 5.3's did come with the 4.8's flat tops and they were the L33 5.3"HO". They used a slightly different cam and bumped compression closer to 10:1 with the flat tops.
Joined: Feb 2001
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From: Cincinnati, OH
Car: '90 RS
Engine: 377 LSX
Transmission: Magnum T56
Re: LM7 with flat top pistons
The L33 (Gen III) 5.3 had flat top pistons as well as all Gen IV 5.3's (LMG, LC9). You can estimate but the only way will be to properly check PTV when the cam goes in.
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