QIKSILVR

99 Silverado 5.3 X-cab,SB Z71
Mods - Volant intake
- Poweraid TB spacer
- Hypertec Programer
- Flowmaster exaust(70 series)
Looking for more power but don't know which direction to go. No SC or Nitros. Thinking of long tube headers, new spark plug wire(Magnecore),maybe replace Hypertec with new Predator? Electric fans? Then I read that the electrics weren't good for towing. I tow a snowmobile trailer and a boat trailer with a 18ft Bowrider on it. Maybe a cam(dont know much about this subjuct), new torque converter? I know I won't be able to do all the mods(buying a new house)but I would like some recommedations and what is worth doing. Dyno and SOTP meter would be great. Maybe I've left some other mods out. I'll be adding synthetics for the F&R diffs, transmission and transfer case. Looking for power everywhere. Maybe I should change my vision and put on a new cowl induction hood and live with the power I've got? What does everyone thing. Thanks in advance. Oh...I live in Canada so all US prices are multiplied by 1.5. Gets expensive fast.

Flem

A set of long tube headers will get you some decent gains. other than that its cam,heads or a s/c the s/c is expensive but is the most complete powerband booster (talking roots/screw compressors), they boost low-mid and top if you are towing low and mid gains will be important. cam heads and centrifigal superchargers boost mid and top end. the old adage always applies, speed costs money, How fast do you want to go?

Hit Man X

First how much money do you have to work with? That way I can guide you in the right direction...

Are you looking to get moving faster from a dead stop or just overall power? That I ask considering a high stall converter will make a world of difference in your 0-60MPH gains. Hell even a 2400 stall is ~700rpm higher than stock! A Yank 3000 (what most on here have) has full towing capacity due to its large diameter and will multiply input torque 2.1 times vs the 1.9 of the stocker. It will feel like you are getting a decent gain in torque with that. I would start here. A 2400 stall is about $400 and the 3000 is around $750.

As your truck is about 4-5 years old now (depending on when built) I'd go for a full tune up too. Fuel filter (makes a HUGE difference if never changed before), spark plugs (NGK), spark wires (MSD), PCV, etc. Max out what you have first.

I'd bet electric fans with a modified thermostat would be fine for towing. Those are a good cheap mod. Score some used Z-28 or T/A fans and pick up some sort of thermostat w/ relay. You are talking $200 and under if you do it yourself.

Long tube headers will yield a large gain in HP and TQ. Arizona Speed and Marine are popular and work great but have two downsides: expensive and have a crappy coating. Doug Thorley recently released a new set of headers that should work well and are priced a bit better. The Other Guys are probably the best built set of headers on the market in my opinion, but they cost as much as the ASM ones and they are mid lengths. $500-750

The Predator will give you more power than the HPP3 will. You could probably hock it on ebay for ~$200 and use that for the Predator. It also has way more options to deal with. Just changing the WOT and part throttle shift points on my old '99 made a massive difference.

Also consider ASP underdrive pullies. 8-12rwhp for ~$200. A ported throttle body is a nice part too. ~$140 for the TB.

On your fluids: save some money and put dino oil in the diffs. Only use regular ATF also, I'd get a TransGo shift kit installed at the same time (about $100). A fluid change will cost about $60-80 anyway so use that toward the labor of the shift kit install. The TransGo will prolong the life of the trans and make it shift way better. Also, '99s did not come with trans coolers from the factory..I recommend installing one of those also. $40 is cheap insurance. GM has some new blue oil for the transfer case, somehow redesigned.

Hope that helps...

QIKSILVR

Hit Man-X...Thanks for all the info. At least it gives me a starting point. Guess I should have been more specific about what kind of power I want. Low to mid range is were I'm looking for improvments. Thanks again for the input. Anyone else have any ideas to help. Thanks again!!

QIKSILVR

Doesn't the Predator have more transmission variables than the Hypertech. I mean you can adjust the shift firmness settings to your liking. Would you still recommend a Transgo shift kit with this?

Hit Man X

I believe so. The Predator is a far better piece than the HPP3. It just raises the line pressure a bunch to get firm shifts. But you can change the WOT points, part throttle from what I am told, and rev limiters. I dunno if it can delete torque managment or not.

The TransGo raises the pressure some with an oversized boost valve but it makes much better use of the pressure already there. Seperator plate holes are enlarged for more flow, springs are changed out for more tension, etc. The best part IMO about it was fixing the 2-3 overlap. That is such a sorry shift in stock form. The kit will give you the firmness you are looking for but make the trans shift so much better.

Oh and most of what I listed for mods will help the entire power band. You can't go wrong with a stall converter first then a better programmer then headers.