Silverado2469

iTrader: (1)

Hey guys, so I have a 2001 silverado. Reg cab shortbed stepside. Right now it has a 5.3l in it has headers exh. And a box tune. Im looking to either pick up another 5.3 or 6.0 which ever I can get my hands on first for cheap. Looking to make 400-450hp at the flywheel. Its a daily driver. So not looking for anything much more than that.

I will either be buying the prc stage 2.5 heads. Or doing a custom port/polish on the stock heads. A mild cam. Something that I can still tow a small boat with. How reasonable is this? And should I go with a forged assembly or will a new stock assembly stay strong for that hp range? This is a budget build. But I dont really have a budget yet. I plan on just buying the block, and slowly piecing this together. Im not in any rush. Would this be a reasonable thing to build for lets say around 3k. With buying a new block? I will reuse all the accessories from my 5.3. So it can be a bare block. Head cam package is about 1500-1800. Stock rebuild kits about 700. Thats 2500. And about 500-700 for a block from a junkyard. So about 3k is what im expecting. I will do all work myself. Unless machine work is needed. I dont want to go FI. I know I could hit my 400hp mark easily with it but theres just something about the scream of a NA motor that I cant stay away from. Haha. Thanks for the advice guys. Im in southern california. If anyome has a 6.0 bare block or a 5.3/4.8 as well.

rhino200099

iTrader: (1)

243 heads and a cam on your block should get you to the 400hp fhp or damn close to it.

Silverado2469

iTrader: (1)

Would it be better to just go with the prc heads or are the 243 heads better?

Silverado2469

iTrader: (1)

Can someone tell me how to figure out compression ratio. Been trying to find out how combustion chanber affects CR. I cant find it. The 243 have a 64.5 combustion chamber. The 806 heads. Have a 61. Will that bumb up or lower compression? If anyone has a formula id appreciate that so I can compare different heads and go from there. Thanks guys.

baronsmith98

iTrader: (2)

Google wallace racing calculators and they have the formulas on there. As far as the forged rotating assembly that is probably overkill for the power range you are looking for and it isnt budget friendly. A smaller combustion chamber will increase compression.

97camaro383

iTrader: (31)

The smaller CC will raise the compression. I had my 243s milled to 62cc to raise compression

Silverado2469

iTrader: (1)

Okay thats what I thought it was. The smaller the CC the higher CR. Whats a good compression ratio to stay at for a street motor? 91 octane only. I was thinking no more than like 10.5:1? Would I be able to hit 400hp with the 243 if I didnt mill them?

FormulaTA327

Wondering the same thing

rhino200099

iTrader: (1)

i didtn know it was that big of a diffrence so yeah you would need to mill them or you could just port and polish the heads you have and put bigger valces in them.

Silverado2469

iTrader: (1)

Okay ill just end up getting the stage 2.5 5.3l heads. Bigger valves, ported polished, etc etc. And either a comp 218/220 cam. Or the tr220. Staying with the stock converter. After doing a lot of research. I found a modern mouse build. In a magazine. They got 415hp out of it with a 212/218 cam and a set of 2.5 heads. So I think 450 is reasonable with the bigger cam.

So next question. I found a block on ebay. 199$ plus shipping. Waiting for a shipping quote.

Its a bare block. I found a rebuild kit for the 5.3 for 600. Comes with pistons, rings, gaskets. And a few other parts. I would need connecting rods. Should I stay woth the 6.1 rods. Or is there a benifit to going with lets say a 5.7. Or 6.0 connecting rod? Does the coneecting rod length affect clearance, CR or anything else? Ive read the longer the rod. The more torque you make? I figure ill just stay with the stock rod length so I dont have to get to complicated for my first build. But I found forged pistons for 500. And forged I beam rods for 300. But the rods are 5.7" not 6.1. What do you guys think?

garygnu

stock cast ls assemblies will handle 500 hp .how many miles on your current 5.3 ? it is better to buy a rotating assembly as a whole kit .don't use 5.7 rods in a ls .a texas speed 224r cam with a 114 lsa will work with a stock stall .the cam you are looking at in a 5.3 with ported heads mite not 450 fwhp.consider a cam from Tick performance or EPS ,they have great lobe designs to make good power .check Texas Speed for rotating prices .

Always2Slow

iTrader: (8)

For what you want to do its ridiculously easy to do on the cheap. If you start out with a 6.0 you will have more torque for towing. I would spend more on the bottom end in getting the 6.0 block then I would a fancy set of heads. I would then grab a set of 243 heads and get a valve job and have it blended in at the very least. You could then grab a cam in the range of 218 to 224 that will make all the power your looking for with the driving characteristics you after in towing. You don't need any special or fancy lobes to do this with either. You can even use an LS6 cam with the 6.0 and make over 400 FWHP with a set of 918 springs or similar and have a very long last valve train.

cobalt964

243 heads, ls2 cam and springs, and a tune. 400ish., maybe a bit more. go to carcraft.com and read their 5.3 cam only dyno specs. they tested a bone stock 5.3 with a bunch of diff cams.

Silverado2469

iTrader: (1)

Theres 158k on my 5.3 now. Im buying a new block just so the truck doesnt have to be down. Its my only vehicle. Besides my bike. So im gonna build the motor. Then do the swap. Should tske me one day to swap motors. And then get it tuned the mext day. Down time one weekend. No loss of work haha. Thanks for the help guys. Im gonna really try and find a 6.0l. To start with. Will be a lot easier to do what I want.

schreurs1

Honestly I wouldn't even start with a bare block. Find a good solid used 5.3 or 6.0 at the junkyard and do your head, cam, and intake swap and you'll have and 400hp motor for a lot less. Search around the yard for one that's been well cared for and you wont even need to rebuild it. Ive had two 5.3s opened up, one with 246k and one with 215k and they look brand new inside. JMO

Silverado2469

iTrader: (1)

Right on. Ill have to go to a junkyard and see about picking up a 6.0

Forcefed86

iTrader: (4)

Or.. just run a cheap $250 GT45 turbo on a totally stock setup. You'll make more power than all of the options above for around the price of heads and a cam.

IMO a 6.0 is overkill and then some for 400 crank hp.

Looks like a stock cam only 5.3 should be able to break the 400hp mark pretty easily too...

224/232 crane cam and springs made 440 crank hp. The LS9 cam that I run (Under $100 new with $60 springs) made over 420chp.

http://www.carcraft.com/techarticles...mparisons.html

Silverado2469

iTrader: (1)

I was really tempted to build a rear mount turbo. But decided that I wanted to learn more about building a motor. Before I through on a turbo. But that is still an option I guess. But with 160k on my motor. I would rebuild it before I through a turbo on it. So I might as well build this more. Put the comp 216/220 cam in it. With a set of heads. On a 6.0 that dynod at 460/430. I think according to a magazine article I read. So in a 5.3. Maybe like 430/390? Thats a very mild cam. And made 345ftlbs at 2000 rpm so I could still tow and have a streetable truck with a stock converter.

Forcefed86

iTrader: (4)

I disagree. 160k is barely broken in from what I've seen on these motors and a great place to start when adding a turbo. My 5.3 had over 160k on it and looked great. I reused the original bearings/rings etc and ran it all year at the 800+ crank hp mark. All OEM hardware etc. I believe reusing the original timing chain was a bad idea however and what lead to it's failure at the end of the year.

The old K.I.S.S. method applies here. Absolutely no reason to "build a motor" if your HP goals are 600whp and below these days. If the motor craps out... buy another stock JY motor and throw it in. Save your money for fuel management and a decent transmission. Even the early 4.8's in stock form will make 600+ easily on the OEM longblocks.

schreurs1

Yahtzee!

That's the theory I am going off of. If you want peace of mind, get rod bolts and head bolts and give 'er hell.