If the 8 gives more HP, and is little more expensive why not do it? Is it not safe to do the 8? When you change the pulley, do you have to do anything else?

 

Check out the vendor's sites. You'll probably pick up a lot of info just looking at what's available.
Personally, I think 8# is to much. You can expect a chip install, change to a cooler plug, and intake at a minimum.
I spent about 2 weeks surfing old posts, asking questions, and calling people before I decided on my setup.

6# pulley
Denso it20 plugs
Line mod Valve
Superchip flip chip
Oil Breather cap
Air Force 1 Intake
Magnaflow Muffler
2" drop
Autolite Trans temp & Boost Guages

 

My opininion is that the 8 over the 6 being only a handful of horses and maybe 10-15 ft. lbs of torque is not worth the extra heat and risk. Again, my opinion. There are several Harley guys running around with 8lb lowers with no problems.

If I go that high, I will probably go to a works or whipple replacement top half so that I get more efficiency at lower boost in hopes of keeping the motor from grenading. I won't do that for at least a year, though.

Ken

 

if you do a 8# you definately need to have a chip,cooler plugs,and a better air system.
JLP has the complete package and can set it up for your needs.
I also added a TB and cold air pickup.
Truck is real spunky and handles great.
3\2 lowering and exhaust change helps
For what it is worth

 

the S/C looses efficiency as rpm increases because the air discharge temperature rises exponentially leading to detonation. I have heard of no problems with head gaskets or bottom-ends so the only problem is avoiding detonation. I have a 4lb. lower with a 3# upper (7lbs of added boost), diablo chip and air intake and the motor will detonate at high rpm unless running C-10 mixed 50/50 with premium gas or the NOS is on (50hp dry shot). the truck is not my daily driver so $4.75/gal. really is not a problem. if I keep my foot out of it i can still run around on premium gas (NOS off). if you decide to go with the 8lb. let the chip programmer know what's up and only nail it when you have C-10 (VP unleaded race fuel) in the tank. DO NOT PUT C-12 or any other fuel that contains lead! it will stop up the catalytic converter.

 

If you add a 6 lb lower you better plan on the chip, CAI and other stuff too... so that's not an arguement that holds water against the 8 lber. My truck makes 12.5-13 lbs of boost now at 2500 ft (usual density altitude out here is 3000+) and the most I have ever seen was on a cool night at 500 ft elevation when it pegged 14 lbs (and ran like a raped ape!) on an on ramp. The L boards seem to agree that 14 or so is near ideal boost--any more and you just make more heat with little gain... even though some are running 16 lbs . I have had no probs with pinging that I did not already have stock--it does occasionally ping at part throttle with a warm engine when lugging in a high gear at low rpm. Go ahead and nudge the throttle enough and it will upshift and the pinging stops. It has done that since I got the truck. Anyway, I personaly do not see a reason to go with a 6 lber over the 8???

 

I definately dont want any problems with the truck in the future. I guess I will stick with the 6# pulley.