Jason 98 TA

iTrader: (4)

Great results!

96capricemgr

iTrader: (1)

I don't mean to be disrespectful but please list 3 specific advantages and why they are meaningful.

sheikss

iTrader: (11)

A.I. for me.

TVWilkes

Easy,

1) Rolled over valve angle from 15 degrees stock to 13 degrees. This will give you better piston to valve clearance. It will also allow for a better Intake port design.

2) Better chamber design. The stock chamber isn't always ideal. When you cnc the stock head it opens up the chamber. So you have to mill them to raise the compression back up.

3) Thicker decks for increased strength over the stock casting.

4) Better water flow design for increased cooling capacity and eliminating steam pockets that will weaken castings over time.

5) 6 bolt design for use on stock or aftermarket blocks.

This is just a few.

BOBS99SS

iTrader: (2)

if budget isnt a big deal i would think afr,trickflow, i plan on doing the prc227

Mike Morris

iTrader: (55)

On a 346 n/a that is street driven a worked GM head is tough to beat

Jason 98 TA

iTrader: (4)

Absolutely that's incorrect. It's actually easy to beat a stock head on a 346. The PRC 227 aftermarket casting moves awesome air on a small bore, has excellent p/v for big camshafts & can have small chambers.

The reality is when you start with a ok shaped stock chamber & cnc machine them your making them larger. The only way to get compression is to mill. Larger valves in a stock head kill p/v clearance also.

With a stock head & bigger valves you simply drop p/v clearance. The result is compression bumps with stock castings require milling which limit camshaft size and valve size.

The PRC aftermarket castings feature a tweaked valve angle for better p/v so you can order a PRC 227 head at 60cc chambers that will still clear camshafts as large as MS4s!!!

Jason 98 TA

iTrader: (4)

If someone's wanting to be budget minded checkout the new PRC as cast heads. They move big air & still offer lots of great features over stock castings.

96capricemgr

iTrader: (1)

Can you provide MEASURED proof of any of that being a genuine improvement?

For example the stock longblock guys are making enough power to nearly discredit statements 2, 3 and 4, and make 5 not really matter until up into 4 digit power.
Number 1 I would go back and refer you to the link I posted earlier, it was a CNC'd 243 vs an aftermarket CNC'd 11 degree head.

1-4 are just salesmanship used by the aftermarket to sell their product and not terribly valid arguments.

Aftermarket casting DO have a place but it is much further down the modification road than many want to believe.

BrntWS6

iTrader: (7)

https://ls1tech.com/forums/dynamomet...-gm-5-3-a.html


Nice read. There are lots of guys making good power on budget heads. There have been a few threads on here lately of guys getting close to 500rwhp on 5.3's. PRC does make a nice 243 head though...I made 442rwhp on a Mustang dyno with a medium size cam and FAST 92. I've got an easy 20 - 25 hp left on a table with a big cam and FAST 102.

Good info in this thread!!

Rise of the Phoenix

iTrader: (27)

That is a great thread with real back to back testing. More of that is needed in my opinion. Would really help a lot of guys like me decide on what heads to go with.

Here is my thing though. Lets say you're lucky enough to find some 243/799 heads for, lets say, $300.00. From what I've seen, they sell for more around $350.00 to $400.00, but for arguments sake, lets just use $300.00. Then, lets say you go with AI as the company to port them. Shipping costs to AI would be around $50.00. Then, you pay for the port work itself, which is $995.00. You're going to need new springs, etc. most likely, so that's going to run another $225.00 (that's what AI sells their spring, retainer, etc. kit for). So now, our budget heads are totaling $1,570.00. I'm not sure if AI pays to ship the heads back to you or not, but if not, then there is another cost. For just a hair more, you could purchase a true, aftermarket, casting head like the TFS 220's or the new PRC as cast heads (not sure on price yet). This is also not taking into account that if you're patient, you could find a set of AFR 205's, TFS 215's, PRC 215's, etc. in the classified section for around that price. I understand that a properly CNC'd OEM head can be great; we've all seen great results and numbers from AI and TEA, amongst others, but you can't beat a good aftermarket head like the TFS 220's, TFS 215's, AFR 205's, etc.

dr_whigham

iTrader: (49)

Jason, is there any ballpark on price for the "as cast" 220's?

96capricemgr

iTrader: (1)

Listen to yourself.
You looked at documentation of an OEM casting beating an aftermarket and finished your thought with
Is that a joke?

wytry

iTrader: (6)

In his defense, he didn't list that aftermarket casting that was beat, nor to my knowledge is it even a popular aftermarket casting. Also, from what I viewed on A.I's site, that 5.3 package, assuming you don't already have the heads, is $1895 WITHOUT springs (correct me if this is wrong). I just purchased a BRAND NEW set of TFS 215's for $1950. It's just my opinion, but even after viewing that thread, I simply could never bring myself to spend that much money on stock castings, whomever they are worked by.

Rise of the Phoenix

iTrader: (27)

That is one instance. Show me more where an OEM head beats an aftermarket casting? If that were the norm, then no one would dish out big bucks on AFR, TFS, PRC heads. The point I'm trying to make is this; when it's all said and done, getting ported OEM heads is going to cost damn near as much as an aftermaket head. There are tons of dyno numbers and track results of cars with AFR, TFS, PRC heads that are making killer numbers and track times, enough to justify spending a little extra to get the benefits that have been gone over earlier in this thread, of an aftermarket casting.

Mike Morris

iTrader: (55)

Excellent points. But you gain some weight with most aftermarket heads,most need or should use aftermarket rockers/guides. Its really a good argument for both sides.

chrs1313

iTrader: (24)

TSP have Aaron send me some PRC227s at 57cc and i will back to back test them vs my TFS215s...Just need you guys to turn down some ls3 valves and it will be an A-B comparision with a car that puts down 525rwhp now and runs 9.8s...If they make more power i will gladly purchase them and I am sure you will sell a ton following the results...

I can document the whole process too, with a bunch of pics and videos

Cosmos

iTrader: (15)

There ya go! Do it up TSP.

01ssreda4

iTrader: (96)

5.3 heads are damn near given away. Quoting new price is silly, takes away the whole advantage of using a stock head.

Also, TFS and other aftermarket heads require roller rockers for about $400 whereas stock heads do not. Hidden cost of some aftermarket castings.

sheikss

iTrader: (11)

I have heard of A.I. heads outflowing trickflows on the same machine on the same day. I wasn't there so I can't validate the statement. What I do know, is that there are some nasty fast cars out there running factory castings.