Hi
I am looking to build up my Silverado. I want to know stock numbers for hp/torque for my base. I have the 5.7 from what I understand that is a ls1 with central point injection system. I have the 4x4. I would also like to know factory cam specs also.

 

in 98' the truck is just a K1500, silverado is just a trim package. the engine in a 98 is far from an LS1. you're dealing with an L31 with 255hp and 330ftbs of torque with sequential central port injection. i have the cam spec's at home, but not in front of me. how much power are you looking for and what mods do you have at this point?

 

I had read the L31 number places. It was RPO code pages tho. I wasnt sure if it was a LS1 varient or not. What you say adds up. After searching and looking for ever and a day I finally found a site that had the numbers for hp and torque. As you said 255 hp @4600 and 330 ft/lb @2800. I am interested in getting those cam specs from you.
As for mods. I havent done a thing yet. I will have the truck paid off soon (bought it used) and then I will start saving to modify. From what I understand the Vortec heads are about as good as they can get so porting or polishing on them is dollars that could build more power in other areas. I am interested in a cam (probably including a PCM modification), headers, and cat back exh. I would like to get the numbers up around 400hp and and still remain very streetable. This truck will continue to be driven daily once the parts are installed. I am more interested in building torque than horsepower. What I mean is I would go with a cam and exhaust that put me around 350 hp and 450ft/lb over a setup that put me at 400 hp and 400 ft/lb. I have been doing alot of research and have been looking at parts but havent bought anything yet.

 

to start with i recomend a good cat back such as gibson or flowmaster. i also highly recomend a westers or ed wright tune for that truck. moving down the line an L35 torque converter along with a good shift kit and servo's will show some nice improvement. for an air intake system, i've been happy with the FIPK from K&N for that model truck. as for a mild cam mod, a readily available from ebay cam would be the LT1/LT4 cams that can be used with the stock springs. anthing larger than about a .460 lift i'd consider changing the valve springs and having the valve guides machined down as the spring retainer can hit along with the valve springs not being able to handle the lift. there is a limitation for a naturally asperated combo since the injectors aren't large enough to do much. i'd consider adding a procharger or similar down the line like this:

 

That looks very similar to the motor my buddy has in his truck. D1SC procharger, 355 JE pision, forged rods and crank, edelbrock performer Rpm heads, edelbrock fuel injection, edelbrock headers and exhaust, built trans, 3500 stall and 3.90 gears.
10 pounds of boost makes lil over 600 at the rollers!!! And its so unbelieveably fast its scary to drive.

 

I have been researching the Cat back exhaust. Gibson definatly caught my eye. Flowmaster is almost a household name they have sold so much. I said before I want to do headers also. Do you know anybody that has used the Gibson Stainless headers for that truck. I need to stay smog legal. I am wondering about fit and if they had any problems. I know that if exhaust temp drops too much the O2 sensors will not function properly. I was planning on getting them Jet coating. If I go with Gibson headers I will probably get their stainless cat back system also. I have also been looking hard at the Edelbrock headers. I have heard lots of good things about them as far as fit and function. With them Ill use the Flowmaster stainless or the Borla. I would like to hear about gains and fuel economy with both setups if anybody has them already.
Whats the tuning you talked about. Is that the PCM recalabration for the cam. I am looking for the stock cam numbers so that I get a feel for where Im at now and get an idea of how far to go up. I do realize that for full effect of the cam to take place that the recal is a must. Do those companies specalize in that programming? I havent looked into that much. As far as necessary head work for the larger cams. I was planning on new springs with any cam installed. Any extra head work needed for the larger cams wont be a problem. Id like to stay away from a cam that needs a stall or very much trans work tho. The trans mods you mentioned are just **** point oriented correct? As a daily driver I dont want the truck to be shifting at 3800 rpm with the kids driving across town.
Supercharging has been on my mind also. I worry about the streetability coming into play there. I wouldnt want to go over 7psi I dont think without going over the bottom end and getting new pistons. I would like to avoid doing anything to the bottom end and pistons.
As I mentioned before I would prefer to build for torque before I built for horsepower. Do the cams you mentioned cater to that type of build? I was planning on cam selection to be more by what Comp or Lunati offered up based on my reprogramming options than anything else.

 

i forgot the cam specs again and i'm back at work. the lift if i recall is .417/.431 and the duration is around 196/202@.050. i'd recomend the XR258HR (08-500-8) along with having the heads fixed to handle the lift. as for emissions legal headers, i've had good luck with the edelbrock ceramic coated headers. as for the pcm calibration, it's nice to get rid of the torque management along with gaining alot of power from having more spark timing and a few other items changed. the shift kit parts are to add life to the trans and to improve shift firmness. i'd recomend buying gm torque converter # 24210922 to go with it. as far as boost goes, 7psi will work nicely. we run 11#'s on a regular basis in the tahoe which he also uses for towing. boost with the P1SC is very responsive and works well under most cases without issue. the whole system worked terrible though when installed and is much better since some changes has been made.

 

What were the problems you encountered with the supercharger. What else that I havent asked about may pop up and give me problems doing a cam and exhaust. do you think my goal of about 100 hp and 140 ft/lb gain with exhaust, cam and a program are easily reachable.

 

I don't think that's going to happen. Even if you changed the heads, cam, and exhaust there would still be the stock intake manifold witht he stock injection system. The injection is what holds back the L30 and L31.
The intake manifold is also the reason these engine respond so well to forced induction. A supercharger will push air past all the internal obstructions in the manifold. Extra fuel comes from either raising fuel pressure or adding auxiliary fuel injectors, depending on which system you go with.
Just keep in mind that making upgrades to flow better requires proportional increases in fuel too.

 

about the only problems we've ran into doing the install was the parts that came in the kit. the b.o.v. was a piece of crap and the plumbing didn't fit very well. with a few modifications to the system it's now working very well. for a swap like that, electric fans are a must.