Hi,

I currently own a 2000 Chevy Silverado 1500 with a 5.3 LM7 and want to get as much horsepower out of it on a budget. A cold air intake and new injectors are a must but I have no clue what I should get for an intake, cam, throttle body, the rest of the build. My budget is $2500. I know that isn't a lot but im trying to get as much as I can out of it and later down the line can maybe spend more to further the build.

Thank you

 

The intake manifold you have is fine. One of the best there is. Leave it alone.

The TB is already bigger than it needs to be. Leave it alone.

Your injectors are entirely adequate. Leave them alone and spend your money elsewhere. Having them cleaned and flow-matched is a good idea; changing them to something else, not so much. Lots of the injector services will sell you a set outright (no cores, no "rebuilding" your existing ones) for less than $250. Money well spent.

Cold air to the TB is a good idea. Make sure it doesn't disturb the MAF too much. You might be surprised how much, in some situations, just rotating the MAF can change the way the motor runs. You might find yourself going through a certain amount of such "tuning" yourself. I certainly have.

A cam wouldn't hurt; depending on gears and tire size, it should either be something in the 206/210 range, or 212/218. Nothing ANY bigger than that. Any number of vendors such as Summit, TSP, BTR, and so forth, have good choices in that range. The valve springs HAVE TO go; even with the stock cam, it'll run better with better valve springs, surprising though that may seem. I have PAC 1218s on my LM7 which still has the stock cam. Made a VERY noticeable difference. Even though that cam, if its lobes thought they needed a bra, Clearasil would take care of it.

A torque converter will really wake it up from a stop, especially if you change the cam. Stock cams are SO low-end oriented, that any "bigger" cam will make it feel soggy on "leave". A converter TOTALLY fixes that, and then some.

What you DO need to CHANGE, without any question whatsoever, is long-tube headers, 3" exhaust all the way from the headers to the street, and a TUNE. I used Blackbear for mine, and it's good; there may be others as well, but I have no complaints about mine.

All of this, speaking strictly as someone who has a LM7 in a 2004 4WD Avalanche.

 

Thank you so much for the detailed response. If at all possible could you send me some links to where i could find everything? I've been searching for different parts and its leading me all over the place. Would a K&N cold air intake be a good choice? I have K&N filters on my corvette and love them.

 

Invest in changing the various engine sensors while the motor is out - cam position sensor, crank position sensor, new temperature sensor. That crank sensor is hard to reach later. Get new lifters and trays. Get the heads rebuilt - check the guides, new valves possibly, three angle cut on the valve seats and new valve seals. Get them milled flat and checked for cracks, especially the heads made by Castech. You don't mention the motor's mileage but these heads need work at around 150,000 miles. New timing chain and gear. New oil pump.

Edit: Don't forget the knock sensors and their wiring harness.

Forget the cold air intake. Its not worth the trouble and I will bet you lunch at any restaurant of your choosing (and probably mine) that it will harm your Long Term Fuel Trims - these are OBD2 engine operating system measured parameters.

Links to find these parts? Ask your machinist where he buys his parts. He has to fit them, not you.

Your $2500 budget is a little low, at least around here.

Rick

 

All of this is good info. For a budget build. I would skip the cold air intake set-ups. The factory set-up will work fine for the hp range you will be in. The only thing I would add to this list, would be head milling. That will ensure that you have good head gasket sealing, and add power. The LM7 needs more compression. Those dished pistons don't help any. Flat-top pistons would be ideal, but it might exceed your budget for this build. Head milling is usually cheap. I pay about $150 at the shop I use.

 

If it were mine, and I was on the budget you are on... I'd get the heads milled, 3 angle valve job, new valve guide seals. Then, flat top pistons, inspect and/or replace the main and rod bearings IF THEY NEED IT. Replace the cam bearings-they absolutely WILL need to be changed. New piston rings... an after market cam is absolutely mandatory! Can't, and WON'T recommend a cam as no matter what cam ANYONE suggests, someone else will come along and say "it's all wrong!". So, FOR ME... I will not go any larger than a 228 cam on the streets. I do not now, nor have I ever built a "race" engine.. I only build STREET/DAILY drivers. Since your budget is so low, I'd keep everything else stock-ish (even the flat top pistons from a 4.8 will work in the 5.3), and just upgrade the cam. I LIKE re-using GM lifters if they show no signs of wear, and the rollers spin with no signs of damage to the roller needles. I'd RATHER run used GM lifters over ANYTHING from China... This is a budget we are talking about so that's why I would keep the GM lifters. You need new lifter trays. Cam wise-I LIKE the Truck Norris, Summits Big Torkinator, or other "smaller" cams... Update the valve springs (depending on what cam you end up running). CHECK and CORRECT your push rod length-search the forums for how to figure out Push rod length. You can build a nice little street motor on that budget.. Just keep in mind as you approach 228 degrees of intake duration at .050" lift, you WILL be changing other things such as injectors, you will need a stall converter, you will need a performance "tune". You will need long tube headers, Y pipe, Xpipe, true duals, better mufflers-etc...... Staying with a "smaller" cam can have you up and running without all the extra expense up front, and you can slowly add the other things later if you want "more"...

 

What's wrong with the engine? If it works fine and has good pressure, I wouldn't mess with it. Get yourself some numerically higher gears and a reflash for the ECU to correct the speedo. 3.73s or 4.10s if you have 3.42 or lower.

Maybe there's more to the story?

 

Totally agree here. Gears and a converter will do more than most realize, and the factory tune can always be made better. Start there if on a budget, and see how you like it.

 

I have a 2000 silverado, mind you single cab.
*5.3 stock bottom end
*243 heads port, polished, and milled .030
*btr stage 3 truck cam
*dual springs .660 & trunion upgrade
* one or the sheet metal 102 mm intake and throttle body, obviously aftermarket intake
*aeromotive 340 pump on e85
*gm 42lb felx fuel injectors with 6an lines
* 410 gears with mini spools
* nitrous outlet plate kit
* mickey thompson et street r 305/45/r17
* external trans cooler with shift kit
sounds like alot but man it's really not, I can jump in the truck and go anyways man with ice cold ac. Truck runs low 13s on motor and high 11s on the bottle. Just an ideal of things you can do in time