BLKWS6

Which heads would give the most power? or is there that much of a difference? i know the 5.3's will bump up the cr easier.

trying to decide. Want to get some soon!! <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

thanks

nc z28

tea s1.5 5.3 truck heads get my vote

BLKWS6

Yeah, i lookin strongly towards the TEA's 1.5's. But why not the 1.5's in the 5.7L's?

Damndobbs

what does the s1.5 mean?


clint

LOnSLO

iTrader: (15)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by BLKWS6:
<strong> Yeah, i lookin strongly towards the TEA's 1.5's. But why not the 1.5's in the 5.7L's? </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Why not just go for the Stage 2s?

BLKWS6

Well, accoding to TEA the only difference is the 1.5 have the stock exhaust valve. the port and valve job is the same. the stg2's have the stainless exh valve if i remember correctly. plus, they are a little cheaper <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

Tin Indian

Ported TEA 5.3L heads flow EXTREMELY well on the exhaust side:

@.200” 138 121

@.300” 201 160

@.400” 251 230

@.500” 284 260

@.550” 295 265

@.600” 300 270

As you can see, the exhaust flow is great. And this is with [Stock GM] 1.55" exhaust valves.

The intake valves are Ferrea 2.02"
I guess you would say my heads are Stage 1.5, although this whole "Stage" business means nothing to me. There is no standardization to any of it.

BTW, these 5.3L heads have had some material CNCd out of the chambers in order to un-shroud the valves. Only .003" was milled from the heads deck surface to insure straightness (the heads are brand new castings). This results in a chamber volume of 63cc and a compression ratio of somewhere between 10.7-10.8 to 1 when the stock graphite head gaskets are used.

Ron,

BLKWS6

ok, this may sound like a dumb question but if i went with the stg 1.5 5.3L heads...do i need to find 5.3l cores or will they take my 5.7's ?
Yeah, those flow numbers are great.

Tin Indian

TEA charged me an extra $300 for brand new 5.3L GM heads. Then they credited my charge card $250 once they recieved my old 5.7L heads. A difference of 50 bucks ain't bad considering you now have brand new heads prior to the machining process, etc

The nice this about starting with new 5.3L heads is that you are getting new valve guides in the process. Ported heads that were [previously] used heads normally never get new valve guides as part of the deal. These valve guides are not to be confused with new valve guide 'seals' that are always replaced.

BTW, 5.3L heads will flow better than 5.7 LS1 heads on the exhaust side (givin the same porting) and valve size. I believe the intake side is about the same when 2.02" valves are used in both the 5.3 and 5.7 heads.

<small>[ March 14, 2003, 02:50 PM: Message edited by: Kimchee and Rice ]</small>

Tin Indian

BTW, Brian at TEA sold me on the stock 1.55" exhaust valve for the 5.3L heads. He stated that with [5.3 heads], going with the added expense of a larger exhaust valve than the stock GM 1.55" valve does not warrant the increase in price vs airflow gain.

Again, on the other hand, the 5.3 heads DO benefit from a larger intake valve. Hense, the Ferrea 2.02" hi-flow valve.

BLKWS6

Yeah, thats who i talked to. He was really helpful with them. now, i just have to pick the right bank to rob so i can get them quicker. <img border="0" title="" alt="[Razz]" src="gr_images/icons/tongue.gif" />

SB

Still haven't seen a response as to WHY the 5.3's are better than say 5.7's milled @.030 assuming the same stage. Compression would be fairly similar if the 5.3's are untouched (around) 10.6ish so again why are 5.3's better than 5.7's??

steve <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

LOnSLO

iTrader: (15)

They flow more on the exhaust side than 5.7 heads.

Tin Indian

WHY ....

Look at this again.

#1. Some folks run big cams, and have piston to valve clearance issues. A 5.7L LS1 head needs to be milled .035" to achieve a 63cc chamber and a CR of 10.8 to 1
Mill them more, and piston to valve clearance may be even more critical.

A 5.3L head needs no milling to get you a 63cc chamber and 10.8 CR. But remember, an untouched 5.3 head will actually have a smaller chamber than 63cc, but some material needs to be removed from the chambers to un-shroud the valves. Thats why you end up with 63cc after all is said and done.

A .035" mill will bring re-chambered 5.3 heads way over 11 to 1 CR

Like I said before, my heads were only milled .003" just to insure straightness. And 3 thousands is literally nothing. So, with basically no milling, I get 10.8 CR instead of the factory 10.1 [and] sacrifice NO piston to valve clearance like a milled 5.7 head would have to achieve the same 10.8 CR.

#2. There is no way in hell that a 5.7L LS1 head will flow as much air on the exhaust side that a 5.3L head will, givin the same size exhaust valve.
Put bigger exhaust valves in both the 5.7 and 5.3 head, and the 5.3 will still outflow the 5.7 on the exhaust side.

#3. Intake... Well they both flow about the same if fitted with the same valve and porting procedure.... tit for tat

I'm not in the head business, so I really don't benifit from what head you buy. Get a quality head from a porter with a good reputation for quality and workmanship, and you should have no problems at all. I am just attempting to show you some of the general differences between the 5.3L truck head and the 5.7L LS1 head.

I would have been more than happy with a set of ported 5.7 L heads, but, for the extra $50 (after recieving my refundable core charge), I got a set of brand new heads instead of a set of possibly high mileage LS1 heads with there high mileage valve guides and numerous previous heat cycles.

_________________________________________________

<small>[ March 14, 2003, 10:11 PM: Message edited by: Kimchee and Rice ]</small>

SB

Thanks Kimchee, good response.

Just out of curiousity, all things being equal(whatever that means <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> ) how much more power (on average) would you guess you would derive from the better flowing 5.3's(exhaust side) as opposed to the 5.7's if you dynoed back to back??

thanks,

steve <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

<small>[ March 15, 2003, 09:03 AM: Message edited by: SB ]</small>

Tin Indian

Good question...Unfortunatly, I don't know.

I have read where exhaust flow is actually more important than intake givin a side by side comparison. Has to do with scavenging the cylinders. Someone said, the better the exhaust scavenging, the more effective the intake is and the more intake duration/lift can be used effectively.

Seems like that is why some of the older design engines favored cams that were big on the exhaust side. The exhaust side of the head really did not flow that well to begin with.

I guess there really needs to be a good balance, but with poor exhaust flow, the intake side (all the way to the TB) is limited in it's abilities to pump lots of air.

Hey, thats just what I read..... Seems to make sense.

Again, the majority of the quality aftermarket heads being used on these LS1 engines seem to be very equal in performance even though the flow numbers may have some differences. Some shine a little better than others at one lift, while another porters head flows better at a different lift.

Ron,

zTrackerz

I was just reading an article about heads in GM High Tech.

They commented the best all around Street/Strip head is the 5.7 liter LS1 head.
67 cc combustion chamber/ intake port volume 200cc/ exhaust port volume 70cc/ cr 10.1.1.

It also commented that the LS6 heads is a tuned up version of the LS1 heads. And if you are looking for all out power these would be the choice. They also offer the D shaped exhaust port for improved flow. 65cc combustion chambers/intake port volume 210cc/ exhausr port volume 75 cc/ cr 10.5:1.

They also commented about the 4.8 and 5.3 stating that they offer no advantage over the LS1 heads except for the combustion chamber size 62 cc. Which offers ease at rasing the cr..

My vote goes with the LS1 5.7 heads. Or if you have the extra bucks the LS6 heads......

<small>[ March 15, 2003, 11:14 AM: Message edited by: zTrackerz ]</small>

Jimmyz

iTrader: (3)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Kimchee and Rice:
<strong> Ported TEA 5.3L heads flow EXTREMELY well on the exhaust side:

@.200” 138 121

@.300” 201 160

@.400” 251 230

@.500” 284 260

@.550” 295 265

@.600” 300 270

As you can see, the exhaust flow is great. And this is with [Stock GM] 1.55" exhaust valves.

The intake valves are Ferrea 2.02"
I guess you would say my heads are Stage 1.5, although this whole "Stage" business means nothing to me. There is no standardization to any of it.

BTW, these 5.3L heads have had some material CNCd out of the chambers in order to un-shroud the valves. Only .003" was milled from the heads deck surface to insure straightness (the heads are brand new castings). This results in a chamber volume of 63cc and a compression ratio of somewhere between 10.7-10.8 to 1 when the stock graphite head gaskets are used.

Ron, </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">The only thing I'd like to clarify with these BIG exhaust flow numbers is HOW are they getting such a BIG # <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" /> ? I'm pretty sure TEA is using a pipe on the exhaust side to get such a big number. However, even w/o the pipe I bet the 5.3's are still flowing 230 cfm ex. and that's a bunch IMHO.

Tin Indian

Don't know how they actually flowed the heads, but these numbers (CCFM) is what came with the "FLOW PRO" Compare Data Report they provided me with the heads. The numbers in tenths were rounded off by me to whole numbers.

Ron,

Jason99T/A

iTrader: (21)

TEA flows their heads with an exhaust pipe attached.