Screamin_Z

iTrader: (2)

I've been talking to several people about this situation but I'm torn between 2 lovers.

I have a FFHP forged 347 w/ -2cc pistons, 228R, LS6 intake, Kooks 1 3/4 LTs w/ Kooks catted Y and custom bullet catback and .040 cometics. Now I'm wanting new heads because mine are not cutting it, I'm seeing guys making 30+rwhp with simular cams as mine and it's pissin me off.

It's daily driven, fed 91 octane, still use the .040 cometics...wish I could find my cam card so I could try and figure it out myself but I want some of ur opinions (pat G, J-Rod...people like that). I don't understand quench and know very little about DCR and I do not know what the highest SCR I can run with on 91 octane is.

From what I've been told the 5.3 has better velocity and able to run higher compression but u have to watch out for PTV. The LS6 is able to handle a bigger cam better just incase I ever wanted to go bigger and is one hell of a good price for LS6 heads and all work done to it. I also see they offer 2.02 and 2.04 intakes but flow the same all the way thru...........so why offer different intake sizes?

So which head would best fit my needs, which valves should I pick and how much should I get the heads decked if any to maximize running on 91? Also, should I ask TSP/PRC to do any more work on the heads like race hand finished?

BTW, I do plan on going with a port matched 90/90 and I'll have TSP do the work before they send the package.

PREDATOR-Z

1- 243 casting all the way, with hand race finish
2- 2.02 valves (putting 2.04 on 2.02 seats is pointless)
3- with .040 gaskets no need to mill

But I think I told you all of that in a PM

Screamin_Z

iTrader: (2)

lol, yes u did and thank u very much for ur input and taking ur time to help me...I highly respect ur opinion.

is the only reason ur suggestion of the 243 heads because of the potential of going bigger in the future i.e. cam, boosted?

bfhawki

I went into TSP and talked to Jason about the head/cam combo I was looking at and asked him what he would do. The cam that I wanted was a 228/232 .588/.595 110 and he suggested that I get it on a 111+1. I had written down the LS6 stage 1 heads and he reccommended their new style PRC Stage 2.5 5.3L head with the smaller 220cc intake runner. He thought these heads would be better for the mild 228 cam.

The 5.3 heads have smaller combustion chambers for better compression without milling and more PtoV clearance. Also, the 5.3 heads already come with the dual spring setup and titanium retainers. He said he would put the 2.04 intake valves in to get the flow up over 300 cfm at .600 lift and that these valves would clear with no problem even with .045 Cometic head gaskets that we used.

This combo made 431 rwhp and 400 rwtq. The graph is in the dyno section titled: PRC Stage 2.5 5.3L 228 Camshaft Results and was posted by Jason from TSP.

I like the heads. I took the cam out because it shook the car at idle and I didn't want that for this car. Driveability was good and great power. I could run at 1400 rpm in 6th gear with a 3.42 gear. I just didn't like the shaking. The cam is for sale in the Parts For Sale section of this forum along with pictures of the cam and cam card.

Just thought I would pass along what Jason suggested to me when I asked him basically the same question you are asking. Hope this helped

PREDATOR-Z

I run the PRC 5.3L heads and with 2.04 PTV is less than with 243's, shoot they are less in stock form. The 243s will flow close to 300cfm CNC with stock valves and you can get the runner in 227>230 cc range.
5.3L chamber is 63>64cc ported and so is 243s.
And I repeat, PUTTING 2.04 valves on stock 2.02 seats is pointless and a sales gimmic, if you do not believe me ask anyone at SAM or other renown porters. 2.04 valves on aftermarket seats then you benefit, that yes, but it costs more money.
Hell going from 2.00 to 2.02 is worth maybe 5 cfm.

When I got my heads they were on of the first ones done at Racetech, they are improved right now, but when the 243 LS2 casting became available, it almost makes the 5.3 castings obsolete. I wish the 243 price was as cheap when I got mine, I wouldn't think twice about ordering those instead of 5.3L ones.

This is their advertised intake flow # on STOCK valved 243's

Valve Lift Intake
.100" 72
.200" 149
.300" 206
.400" 256
.500" 287
.600" 306
.625" 310

They flow better than 2.04 valved 5.3Ls (if race finished), are they worth an extra $200, you Betcha

ls2 bait

iTrader: (11)

last i heard the prc heads were in the 237-240 range on the ls6 and about 220 on the 5.3. prc also says the combustion chamber is 61.1 on the 5.3 and 64.5 on the ls6. all the while flow numbers seem to be with 2-3 cfm of each other. so maybe u know something other than what ive been able to dig up over the past few months? all this is based off the prc heads only. seems as though hes still basicly a stock ci motor the smaller runner would greatly beniefit him in the lower end of the spectrum imo. but im always up for input from those who are more knowledgeable than me.

The Sad

iTrader: (8)

I would be interesting in more info as well. I hope I didn't make the wrong choice, as I went with the 5.3s. I did get the 2.02 valve though. On the phone they said that the 5.3s with stock gaskets would clear with a MS3. They also mentioned that the combustion chamber was about 62 or 62.5cc?

PREDATOR-Z

There are 2 versions of 243 LS2 PRC:
1- The first version that was 237 cfm runners
2- Newer version with smaller 230 cfm runners

You can order either, it is a matter of CNC program.

> If PRC 5.3s are indeed 61.1cc chambers, they have been milled. With a hand race finish they are more in the 63-64cc (remember I own a set).
> Stock ci motor has less to do with runner selection than with the type of cam you are running. With a BIG MS3-4, small runners are a band aid fix to get some more trq down low (velocity), while taking away from top end where the cam performs.

Now, you can go either way 5.3L or 243s, but what I'm trying to say is, avoid trying to save $200 for 5.3s and do it better from the first time and get 243s.

1- They flow better (since stock valves outflow a 2.04 valved 5.3 if race finished)
2- more PTV clearance (smaller valves)
3- Better chambers

Guys, a little over a year ago 5.3L was the choice of budget heads because LS6 243s were 3 times as expensive.
When LS2 243s came along, that gap was dramaticaly reduced, now it is only $200.
The 243s are a better head, better casting, better flow, better PTV and the best budget choice part for $$$

cantdrv65

iTrader: (3)

Listen to Predator he's absolutely right. You cant beat the 243 castings...

I have the 237cc version 243s and gained torque/power across the RPM range with the 228 cam. The small runner hype is way to overplayed on this site...There are many other considerations.

Screamin_Z

iTrader: (2)

Thanks Predator_Z and cantdrv65. would u recomend the 230 intakes over the 237 since the 230 should have better velocity down low or does it even matter? u also suggested not milling the 243s...keeping thier stock cc, with hand race finish will that open up the cc and would I gain anything if I did mill down the head...or is it just pointless? what exactly will the do when they hand race finish and how much flow will that gain accross the board?

cantdrv65

iTrader: (3)

I dont know about the hand port finish I just slapped em on CNCd.. They are proven performers. Milling or going with a .040 gasket for quench is your choice personally Id recommend the stock GM MLS gaskets for the best seal. Id also go with ARP headstuds you'll be glad you did... Thats what I used, along with the stock sized valves. The only option I went for was the Gold Dual springs and tit retainers kit. I think the current version of the PRC 243 head is 230ccs, regardless it really isnt going to make a difference with your setup IMO.

Screamin_Z

iTrader: (2)

ah, 230cc...I see that now.

well I'm not going to get them hand finished untill I get Predators answer and talk to TSP to see if they can do what he suggest. I am running a .040 cometic already so I'm not goning to run a GM MLS gasket. I'm also not going to use ARP headstuds...if anything I'll use thier headbolts but I'm sure I'll just go ahead and use GMs headbolts. I have that already and since my bottom end is forged, I'm using a MLS I'd rather break a headbolt than anything else. I've even thought about switching to the 98-01 head gaskets if I use ARP headbolts so I blow a gasket instead of busting anything else. call it insurance if u want since I will be running nitrous. The main reason why I'm not going to use ARP headstuds is because I have a cowl in my way...PITA to take off/put on the heads.

thanks for ur input

Screamin_Z

iTrader: (2)

it's settled, after a long talk with Predator-Z...what he told me in the first PM...

243 castings
hand race finished
.040 gaskets
2.02/1.57

thanks again Predator-Z

PREDATOR-Z

Anytime

Bader-X

iTrader: (2)

so what do they do in a hand race finish and how much will that add up flow and money wise?

ls2 bait

iTrader: (11)

ill be curious to see how this does as tsp just did one with the 5.3's recently. anxiously awaiting some numbers good luck bro.

crazylane

iTrader: (19)

I have a quick question, I plan on going with there head cam package, and I would like to get the 243's with a Torquer V.2. I have read into this post and from what I take it, they come in two different intake runner sizes or since it is the package deal you get what is with the package? Can I have a choice, or would I be paying more for it?

Sorry if I hijacked this topic, I did not mean too, I just did not want to start another one for this question.

Thanks,
Lane

99zman

iTrader: (23)

subscribing..

oange ss

iTrader: (50)

i also got the first run 5.3's, i would get the 243 if i were you

chriswtx

iTrader: (5)

curious about the hand finish as well...