yadontmention

i have 2004 chevy silverado with 5.3l iron block(lm7 i think?). its been leaking oil for awile i think its the rear main seal. i had it replaced the guy told me it was loose in the bottom end which would cause it to leak again (prolly a bad mechanic. didnt know it at the time) i was wanting to add more power and also get the oil leak fixed. i was lookin to add in a new cam and whatever comes along with that. i just need a idea of what needs to be done if the bottom end is loose. can i bore it out? just new bearing and sleeves? any help or advice is much appreciated. also i last year i had true dual exaust put on and added in a throttle body spacer now the truck runs lean. any advice with that would help also

G Atsma

How is your oil pressure? IF the bottom end is loose, new bearings/turning the crank will fix it. Cam bearings could still be OK. You likely have the LM7. If you want more power but otherwise same driving characteristics, put the LQ9 cam in. It will give a nice boost in power throughout the range.

yadontmention

after i had the work done the oil pressure is sitting lower than before. before i had the seal replaced it was high if anything which i know isnt a bad thing. now it hovers around a quarter up the gage. before it was like 75% up the gage. could the guy have just done some bad work? also with the cam thing im wanting to go further not just the cam maybe port the heads or get new heads, flat top pistons, and maybe a 102mm intake. i like getting in the mud so a mild off road build is what im going for. also i have a 4l60e will it hold up with that much more power or will i need to do something with it to?

G Atsma

Which state are you in? If emission testing is part of the game you have to be careful with mods.
You can get your heads CNC ported (keep your intake manifold, it flows well) and the cam I mentioned will all pass emissions.
How much low end power do you need to hang onto?

yadontmention

im in north carolina. well i would like to be able to tow also. so i would think i need low end power.? its also a daily so im not wanting a hot rod but i still wanna be able to have more than enough power to push some 35s through mud.

Darth_V8r

iTrader: (4)

You may actually want a small cam with a tight LSA. Towing with 35s and a 5.3. I would almost do something like 210/216-110+4.

G Atsma

Cam Motion has that cam but with 115LSA, +3, but I would bet they'll grind whichever LSA and advance you desire

yadontmention

can u explain alittle more? i dont know much about cams or what the numbers represent. why would a smaller cam be better? and when installing a cam do i need to do anything else to the engine to accommodate the new cam?

yadontmention

ok dont give me to much hell for posting this but i wanted something similar to this maybe toned down alittle.

Block: Stock
Crank: Stock
Rods: Stock
Pistons: Stock 4.8-liter (flat-top)
Cam: COMP XR281HR .571/.573 lift, 228/230 duration split, 112 LSA
Heads: TFS GenX 205
Intake: FAST LSXR
TB: FAST 102 mm
Headers: QTP 1¾-inch long-yube
Peak Power: 501 hp at 6,500 rpm
Peak Torque: 452 lb-ft at 5,400 rpm
Torque Curve: Exceeded 425 lb-ft of torque from 4,200-6,100 rpm

is this to far for a daily or will this work?

yadontmention

what do you guys think of a 220/224 112 LSA?

G Atsma

It would work, but for what you want, 102 is more TB than you need, the cam could work, but a little less duration would not hurt.
What you describe above is-
a stock short block (GOOD!),
a lumpy cam (a little less will do),
TFS heads (Good, but porting yours will do YOU as much good),
an expensive intake (not really necessary, the truck unit flows surprisingly well)
a big TB (more than this engine can use)
Bottom line- You can get the power I think you want from your engine spending a lot less than the above motor would cost. FAST is VERY pricey for an intake you can barely use.

G Atsma

Now you're talking! That cam will do you more good than the one further above. Who makes this one?

yadontmention

thanks atsma. Trick Flow Specialties .575 lift, 220/224 duration split, 112-degree LSA i think i would have to change the lifters and stuff also right?

G Atsma

yadontmention

would you rccomend the 4.8 pistons or should i find some flat 5.3 pistons? i really wanna go alittle further than just cam but not overboard

G Atsma

4.8 pistons and flat 5.3 pistons are the same piece. It's a common 5.3 upgrade to use 4.8 pistons to raise compression. Good idea!

yadontmention

and would u go ahead and change heads or just use the stock ones and maybe have them shaved? or do i even need to worry about heads?

yadontmention

was messing around on the trickflow page and found they sell a whole kit. is this something that might fit what i need? https://www.trickflow.com/parts/tfs-k306-500-460

G Atsma

I would send the heads to someone like TSP and have them do a CNC porting/valve job. For $750 they will thoroughly clean and disassemble the heads, do a CNC valve job and CNC the ports, mill to your spec, then reassemble with either the parts they came with or at extra cost, better springs and retainers (if needed). This is regarded as a good deal by many.

G Atsma

Not sure you need all that. It's a good kit, but I bet it costs a lot more than you would spend going with the plan we are discussing here. No pricing was , but I bet it's not cheap.