Chiphead

iTrader: (2)

Hey, My 5.3L block has just passed mag at the local machine shop. What prep work should I have them do to it? The motor will be a cast piston, stock rod combo for my '04 ECSB 2WD. 862 heads milled for 10:1 compression and cam/headers and a mail order tune. Basically a warmed-over motor set up for more power without killing the tranny.

Here is the stuff I asked him to quote:

bore&hone, install cam bearings and galley plugs.
Turn crank and balance rotating assy.

Anything else I should have done while it's at the shop? Do I need the decks cut to run cometic head gaskets?

Chiphead

iTrader: (2)

Nobody? I've not built a Vortec before and I don't want to miss something stupid.

What year did the cam bearings change? I think my block is a 04 but not sure. Did the cam bearings and head bolts change at the same time? Will it be obvious to the shop if they try to install the wrong cam bearings? I don't know how many LS motors this shop has done, because I haven't used them before.

Any suggestions on hyper pistons or ring packs to use with this setup? I figure I'll have to use the 5.3L floater dished pistons and then mill the heads to get 10:1. I'd like the option of running the cometic gaskets to set quench depending on where the deck height ends up. So I'll ask again- is the stock deck surface smooth enough for cometics, or should I just run MLS? thanks...

1FastBrick

iTrader: (17)

They list cam bearings for 97-03 and 04 up. Your machinist should measure the bore and order accordingly.

The block should have a casting date on it to identify it. You can also check the hole depth of the head bolt holes. If you pulled it apart, you can id the existing bolts to determine what you need.

As far as the deck goes. Ideally you would assemble the block and check the deck height with the piston at TDC. They will be out of the hole but depending on the block casting 1 side could be higher than the other. You would need to mill to correct this.

If you haven't already ordered pistons, you may want to consider going to a flat top 4.8 piston and changing to a different head casting. Also the rods you have will determine whit type of pin you need.

Cometic's are MLS so I don't know what you're getting here. Cometic's are made in Various thickness whereas the factory ones are only available in 1 thickness. Only you and your machinist can determine if the finish is good enough on your existing block. We are not there to physically inspect it.

Chiphead

iTrader: (2)

Thanks brick. The plan is to use the small valve heads because they'll make more low end torque, and I don't want to make so much power I kersplode the 4L60E and stock driveline. Not to mention they're much cheaper than 799 heads.

How much power can a stock-ish 4L60E take?

1FastBrick

iTrader: (17)

I just broke an upgraded 4L60E with a stock 5.3L. What ever let go was hard parts. I won't know till I pull it and dissect it. They can't even take abuse behind a stock engine... When it let go, I wasn't even abusing it. The tighter they are inside helps but ultimately it will not hold up to abuse. The money to rebuild and upgrade the parts your self is about what what it would cost to buy a stock 80E and swap it.

The small valve heads are not gonna make more torque the way you think.

I am not sure you can mill the stock 862 heads enough to get the compression you're looking for with a dished piston. You might achieve 9.8:1

You don't need a 243/799 casting. You can pick up the 241 heads for a reasonable price and mill those to 64CC for use with a flat top and easily achieve the compression plus increase the flow.

Chiphead

iTrader: (2)

So is there any downside to 241s and flattops in a 5.3?
Any years more desireable?
Any piston to valve concerns with mild cams?
Will the centerbolt 241s accept vortec valvecovers?
Will the truck exhaust system (manifold or header) bolt up?
Are all the accy drive bolts in the same locations as a truck?
Can I use the 5.3L MLS gaskets, or do I have to use graphite?
Is the chamber diameter larger than a 5.3 bore? Thanks! this might change the direction of the build...

1FastBrick

iTrader: (17)

Shouldn't be any downsides.
The best would be a 243/799 but core prices are anywhere from $350 up
The 241 has a slightly larger combustion chamber but they're more affordable at around $200
241 are center bolt, no issue there. FYI The LS platform parts are mostly all interchangeable.
Exhaust ports are the same bolt pattern.
Accessory holes are the same.
MLS gaskets are fine but you need one from a 5.7L due to the slightly larger combustion chamber. The only time a Graphite gasket is required on these engines is when the head has notch in the deck surface. See attached image.

GM built an L33 5.3L engine that uses the flat top 4.8L pistons with a 799/243 head. It used this head gasket part number 12589226. I believe you can buy a pair of the same head gaskets under 12498544

Chiphead

iTrader: (2)

I just scored a set of centerbolt 241s from a '01 WS6 on Ebay. They'll need going through but I got 'em pretty cheap. So it looks like I'm going the flattop/big valve route.

What do you guys think of the speedpro hypereutectic pistons for a N/A motor?

I know, everybody says "build a forged 6.0L", but I'm looking for realistic power on a realistic budget.

Chiphead

iTrader: (2)

Soon I'm going to have to provide pistons and other parts to the machine shop. I'm having trouble finding parts like oversize rings, etc.

Who are the big players when it comes to parts for the 5.3L? I need pistons, rings, gaskets, bearings, etc and I'd rather get all the right parts than try to piece it together. Who do I need to call?

1FastBrick

iTrader: (17)

It's not that hard to find. Your machine shop should know where to find this stuff.

Hastings makes the rings

Speed Pro and Mahle have stock replacement type pistons in various oversized.

I only use Gm Gaskets so I Either buy from a vendor on here like SDPC or I find them elsewhere depending on how soon I need them.