Stoichiometric

iTrader: (10)

I just picked up a Radix from BlownChevy, definetly the right guy to talk to!

I am curious what experience anyone has had with the GT-7 cam. I know the GT2-3 (207/220 .571/.578 118.5) is the tried and true "Radix cam", but the GT-7 ( 208/230 .554/.546 121CL) has even less overlap and more exhaust duration, which is good right? I want to use my Crane gold 1.8 rockers, which makes the GT-7 a better candidate to keep the lift reasonable. What do you guys think?
By the way, this is a 3/4ton 6.0L truck.

Thanks again BlownChevy for the deal on the Radix

Mr. Sandog

How much more negative overlap do you need? The GT2-3 has negative overlap, so you really don't need more if this is your concern. Of the difference between the two cams, from what I understand, the extra exhaust duration of the GT7 is for those setups that have more restrictive exhausts, i.e. stock exhaust manifolds. Maybe one of more experienced cam guys will give you their experience. I would also suggest posting over at LS1Tech if you want to tap into additional knowledge.

1slow01Z71

iTrader: (36)

Thought you were going turbo and all that or is it for the tow rig?

whitt1

I personally run a GT2-3 with 1.75 Comp rocker arms and am pleased with the cam,it makes good power from 1500 to 6600rpm,idles decent and makes good vaccuum.Kysilverado runs a GT-7 with a Radix setup and he seems to like that cam.I talked with the guys a Lingenfelter and they suggested the GT2-3 with a Radix setup when I ordered my cam.

trever1t

iTrader: (14)

I was going to say the only Gt7 user i've seen is Kysilverado and he seems to do well with it too. As TBSS was saying the GT7 might offer aid to a restrictive exhaust setup but mine, with shorty headers, does fine with the GT2-3.

Stoichiometric

iTrader: (10)

I don't know how much negative overlap I actually need . If I didn't already own the Crane 1.8 rockers I would just go with the GT2-3 without even thinking about it. If I do the GT2-3 with the 1.8's I'll end up with more lift than I want. The GT-7 will make the lift work out perfect. I guess I need to decide between stock rockers with the GT2-3 or Crane 1.8's with the GT-7.

I am still building a turbo motor but that will now go into my 1964 Fleetside. I really wanted to turbo my 2500HD, but the '64 will allow me all kinds of fabrication freedom and a faster timeslip eventually . The Radix will go on my 2500HD.

Stoichiometric

iTrader: (10)

I will have long tubes with 3" dual exhaust eventually, so the restriction will not be a factor in cam choice.

Thanks for all the help, I am sure I will have more questions seeing as I haven't even recieved the blower yet.

Mr. Sandog

One of the cam goals with a blower is zero overlap....negative overlap is fine as well but once you've established zero overlap, anything additional (i.e. more negative) is unnecessary as far as bleeding off boost. That was the reason for my comment.

Given your exhaust setup I would just go with stock rockers and the GT2-3, and sell your 1.8 Cranes. There is always someone thinking bigger rockers are better (even though they often create more problems than they solve).

Stoichiometric

iTrader: (10)

I am sorry, I didn't realize that I made it sound like I was laughing at what you said. I was trying to laugh at myself for not knowing what I need or don't need. I appreciate your help and don't want to sound like I came off wrong.

You are right, the 1.8 rockers seem to be more trouble than they are worth to change my cam specs just to make use of them.

KySilverado

iTrader: (7)

I like the GT7. Is it better than the GT2-3? I can't say. I generally dyno lower hp and torque numbers than similar setups with the GT2-3 but I also generally pull better ET's with lower MPH than similar setups running the GT2-3.