lift limits on zz4 and fastburn heads
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From: southern maryland
Car: 2012 Ram express
Engine: 5.7 hemi
Transmission: auto
Axle/Gears: 3.55
lift limits on zz4 and fastburn heads
what makes them both only except .530" lifts is it the valvesprings or will they have to be machined? I plan to use the fastburns with a .600" lift hyd roller cam
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From: Philly, PA
Re: lift limits on zz4 and fastburn heads
When you're talking .600 lift it's probably both at that point. The cams they put in the factory crate motors (ZZ4, Fastburn 385 and ZZ383) are all under .530" lift. The ZZ383 is the highest at .528 on the exhaust. For sure the springs, probably some machining as well.
The ZZ4 heads are definitely not worth lifting the valves that high- the port is already stalled well below that point. The Fastburns I don't know, but they're probably better suited to lifts that high.
The ZZ4 heads are definitely not worth lifting the valves that high- the port is already stalled well below that point. The Fastburns I don't know, but they're probably better suited to lifts that high.
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