Flyer,you could have the chambers machined larger or run 6.0 heads,but a thicker head gasket would be cheaper.

 

I would like to do a head cam swap on a 5.3 instead of building a 6.0. I would love to be able to lower the CR when I did this so I could crank up the boost.

Don't the 6.0 heads have a larger bore chamber that would make it funny fit on the 5.3?

 

There aren't many differences between a standard 5.4 and the lightning motor. And it(5.4 Ford) still isn't as good as the LS1 as far as strength or performance. Plus I don't think anyone is going to break a crank or blow a head gasket with some additional boost on top of a 1 point increase in the CR . The car guys with ATI's ect have done some larger boost on stock motors.. The same limits of boost would apply? Wouldn't they....Just make sure you have the fuel to go with the boost.

As far as the lower CR, I'm not sold on cranking compression being lower making it easier to handle boost either. The effective compression ratio is more important.. The lower static CR should allow you to run more boost w/o Detonation but its not worth it unless your getting very serious about the boost.

 

I think the weakpoint ends up being the stock pistons. They don't tolerate detonation very well. Its a very hard and brittle piston that will crack like a spider web and the piston literally will fall apart. The lower static CR does allow you to run more boost w/o detonation and that was exactly my point. We are talking about street driven trucks running pump gas.

 

In Arizona is the premium 91 octane or 93 octane?I run a 3" pulley on my 5.3 Radix with no problems.I do put 104 octane in to run at the track and mix xylene for about 98octane on the street.I do run a 160 degree thermostat.

 

We only have 91 here in AZ. Have you ever run it with just premium pump gas??? How much boost are you seeing with the 3.0 pulley??

 

Yes I have run on just premium to drive to and from work I don't think there would be a problem with the 93 unless I made repeated runs or ran with the engine hot and heat soak became a factor.If I'm running on 93 octane I usually keep my foot out of it.

 

My point was you can tune around detonation and still go with some more boost Run it rich @ WOT if you have chitty fuel. I agree about the pistons, but there's room for boost. Just wish we had a bullet proof tranny like the Ford Automatic

 

How much boost does it make with the 3 inch pulley?

 

9 1/2 LBS of boost with 3" pulley climbs to 10 1/2 at my 5800rpm shift points.