Tan327

iTrader: (15)

I'm sure they out flow the 5.3 heads, but the compression loss wouldn't be worth it.

onebadrubi

Thats why LS6 heads would be nice. FLow just as good as the 317's but wont lower the compression. From what I understand.

READ BETTER mr. im faster then you n/***!

Tan327

iTrader: (15)

I'm confused, I was talking about the 317's not the LS6's..

I think YOU need to read better!

onebadrubi

In my response to richard yes. Because of what he was saying about the ports and chambers on his Edlebrock heds. But the LS6 heads dont lower the compression, my recommendation for his motor build.

Keep in reminder im only throwing out suggestions and not bashing what richard said, He is ALOT more intelligent then me here. lol

Tan327

iTrader: (15)

Still gonna lower it, but not as much as the 317's:

6.0: 71cc
LS6: 65cc
5.3: 61cc

Blue5.3

iTrader: (2)

Patriot shows LS6 head with 59, 64 and 68 cc. So you could use the 59s right?

tdrumm

iTrader: (18)

Be careful with valve size, too big and you'll run into valve shrouding which hurts flow. I wouldn't go over 2.00 intake and 1.57 exhaust on a 5.3.

The data on the WCCH/Edelbrock heads is pretty good and comes with a 59cc chamber unmilled. For a max effort 5.3, I'd run these heads for sure.

Richard@WCCH

iTrader: (3)

Hey,hey, hey!!!! Don't ruin my reputation of being an idiot!

Unless I missed something in the original post, I made the cylinder head recommendation based on the combination of the Edelbrock's small port crossections, valve sizes and chamber volume. I'm not aware of any other head company who make a CNC ported head specifically for the 4.8l and 5.3l engines and their small cylinder bore size. The 6.0l heads have less flow and a larger port as cast, not to mention the much larger (71cc) chamber. Compression will be important to seeking 400rwhp from a 5.3l engine. The Edelbrock heads have a 59cc chamber as delivered, but they can also be machined to 54cc with a .030" mill. That'll raise the c/r to the mid 10:1 range. The LS6 heads have a chamber volume of 65cc as cast and will also reduce the compression ratio, however they can be easily milled to the stock 61cc chamber size of a 5.3l head. The chambers on both the 6.0l and the LS6 heads will extend beyond the head gasket bore size of the 4.8l/5.3l engines. It's a less than ideal setup when reaching for higher power output.

Hope this makes some sense.

Idjit

onebadrubi

so people that are putting 317's and LS6 heads are actually messing up and the chambers and bore isnt exactly a perfect line up?

IS their only one stage of 5.3l Edelbrock heads? Or is their a wild setup that flow alot better and may not be as street friendly?

Richard@WCCH

iTrader: (3)

Yes, you have it correct. All those installing the LS6 and 6.0l heads on a 4.8l/5.3l engine are going to have a pretty large step between the chambers and the cylinder bore. Our Edlebrock chamber diameter is the same size as the stock 4.8l/5.3l bores therefore the stock head gaskets can be retained. The heads are setup with 2.0"/1.57" valve sizes which are about the largest practical sizes to fit these bores.
I only have one CNC port and chamber program for the Edelbrock 5.3l configuration. I don't know that a larger port head will work much better for most street driven applications, but if there's a large demand for such a thing, I would consider making a program to fit.

Richard