I'm about to throw a few pieces of paper in a hat with companies listed and pick one. I'm stuck between PRC 5.3 2.5's or the TEA LS6 stage 2's.

 

I'm leaning very heavy towards 5.3's for my 224R cam from TSP

 

Patriot all the way, the issues they had in the past are just that "in the past " . You will NOT find better customer service ANYWHERE and their heads are assembled with some of the finest components available !

 

The PRC heads are also assembled with excellent parts. But the bottom line is,based on dyno results the PRC heads will out power the Patriots all day. IMO, that makes the PRC heads a much better value.

 

We're currently finalizing a larger 2.5R valve/port option for guys wanting 317cfm+ air flow from a $1400 a pair cyliner head!

Here's the pics of the new rocker arm clearance & PRC logo!






Here's the newly updated 5.3l intake port:





Here's the newly updated 5.3l exhaust port:





Finally the newly updated chamber:

 

any of these companies willing to quote a price to port a bare unassembeled set of new heads that i already own?

 

Complete CNC porting will run you $400 and for the CNC valvejob and reassembly you would be looking at an additional $250. If you need the heads decked let us know and I'll throw that in as well!

Jon
Texas Speed & Perf.

 

Base your decision off of track times, not dyno numbers. Every dyno reads different, as do different flowbenches.

 

I would like to see a same day dyno comparison between the PRC heads, Livernois heads, and the TEA heads. I bet they would all be pretty damn close and they all cost about the same so you can't go wrong with any of the three.

 

After reading Patrick G's thread on how to make 500rwhp I wanted to ask a few questions.

He says a LS6 intake cuts off at about 265cfm. Fast 90/90 at 275cfm and ported 90/90 around 280cfm.

So if I understand that right, a head that flows 300cfm, 35cfm of that is never going to be used.

If this is true, why do companies keep making heads that flow up top so much and don't concentrate on low-mid lift. Please understand that I know nothing about the characteristics of cylinder head flow thats why I am asking these things.

I have been working on cars for a long time now and have learned you can't have things both ways. So if you don't design a head that flows at high lift and focus more on low-mid, wouldn't that be more practical for these engines with plastic intakes.

For the thousand dollars it costs to go ported 90/90 you are only gaining 15cfm? Thats a lot of money.

So am I getting this right? Especially for street budget heads, we should be more focused on low-mid lift numbers than what they flow up top?

Thanks for any insight.

 

I compared the Patriot heads and the PRC's

Patriots PRC
.300 194 208
.400 242 257
.500 274 290
.600 296 312


These are just the intake flow#'s. I know there is differences in flow bench's, if they use a exhaust tube or not and so on. On paper the PRC's look better.

 

It would be interesting if like GMHTP did a shoot out with the 5.3 heads.Take the TSP 2.5 5.3 heads (the NEW ones) amd put them up against TEA's stage 2.5 version. Theres anough interest in them. They truly are a get head when worked. Added compression, build great port velocity and very affordable for the average joe

 

Jon aren't you sick of beating the drum for your son Bert? Also nice work on the pimping of a non-tech advertiser. You do realize if Berts products worked SO great and made so much power it would sell itself. Nice job & carry on

 

Do you have a hard on for them? You must if you quoted his post from MARCH just to reply to it 8 months later.

 

The LS6 intake cut off around 265cfm in the testing some friends and I did back in 2002/2003 so that sounds right to me. I don't know about FAST, it wasn't out back then.

None of the flow numbers mean a whole lot unless the head is flowed with the intake that's going to be used. Likewise, flow benchs vary etc. I always have heads flowed with the intake I'm going to use. Gives a better baseline etc of what you really working with.

I think the peak 300+ cfm stuff is pretty much sales numbers. There are also other intakes that can/might be able to use the additional air flow. Take the new Edelbrock as one example. Some of the carb intakes can probably use the extra cfm. The market isn't just cars with LS6 or FAST intakes.

Another reason some of the heads are ported to keep the peak numbers up high is to make sure the intake port doesn't stall with the high lift cams that are used with these engines.

An intake port stalls when the the airflow drops off at higher lift etc.

stalled Bubba's heads Billy Ray's heads
.500 lift 280 cfm...................278 cfm
.550 lift 285 cfm...................282 cfm
.600 lift 275 cfm...................285 cfm

I'd rather have Billy Ray's if I was running a .600 lift cam because the port doesn't stall for the cam lift I'm using.

A better example would be the flow and stall characteristics with the intake in place...

When an intake port stalls the air doesnt flow as well. If it's bad enough the port will get turblance and result in power loss or less of a gain.

The higher cfm is also a measure of how easily the head flows etc. The flow bench isn't exactly the same as the engine running. Often the mid number increase some as well as the peaks numbers creep up to a degree.

There are some head out there that focus on the mid lift numbers. However, if you listen to folks they'll almost always talk about the PEAK. Just like with the dyno stuff it's all about the PEAK most of the time when it should be more about the area under the curve for the operating range.

15 cfm could be 20 to 30 rwhp in some applications. Only the builder or the buyer can answer if that's worth it to them. Often that 15 cfm might be 5-10 rwhp or less depending on other stuff.

Example a given head might flow

235 cfm with the LS6 intake at a given lift...the same head might flow 238 cfm with the FAST.

I'd look read hard at the .200, .300, .400 .450 flow numbers...however that data is better if you can find the flow numbers with the intake your going to use.

Do your research and look at that the racers that run well have on their cars as far as cylinder heads go. We all have our favorites or shops we've worked with on our cars etc. Pick a reputable shop and go with their product and you won't be disappointed. I think all four listed in the poll above make a quailty product. When you see a happy repeat buyer that's says good things about a given shop cylinder head work and quality.

 

trickflow as cast are good for the money but you have to buy 300-400 dollar rocker arms which takes you up to 2 g's

 

Not meaning to add to an old thread that's been dead since April, but recently there was a guy who made 417rwhp/425 rwtq with an LS1, bolt ons, stock cam, and Advanced Induction heads.

Here's the thread if anyone's interested https://ls1tech.com/forums/dynamomet...stock-cam.html