JoesC5

PRC265 heads(9% more air flow intakes and 12% more air flow exhaust vs stock heads) with Ti intakes and SS exhausts with PRC springs, retainers, etc. stock compression.

39,000 miles on engine and 12,500 miles on heads.

Oil changed annually regardless of mileage but not under 22% life remaining. Mobil 1 and Valvoline syn. K&N oil filter ad Mobil1 oil filter.

stock cam

Street use to 6800 RPM.

MyLastCorvette

WCCH, I'm going to start installation soon. The finest workmanship I have ever seen. The pictures don't show it real well, but Del West makes the Ti intake and Ti Exhaust to Richards specs.

Just a side note, my Very Carefully broke in and Very Carefully Maintained 9k engine; Has two exhaust valves/guides Way outa spec. I had so much tied up in this rebuild I didn't want the additional cost of having WCCH measure each one. (what difference would it make anyway) I can wiggle the valve in the guide, side to side, and can hear tink, she's out. When I get bored as winter wears on I will set up my dial indicator and try to get a measurement.

The intakes and most of the remainder of the exhaust had very little, to no discernible wear...

Used aggressively at times.
Engine is stock except for the head work.
Oil, Amsoil 0-30 Signature Series, once a year @ approximately 1k.

RamAir972003

Nice....

RichieRichZ06

Joe, have you pulled the valve covers and removed a couple springs to test the guides again? I ask because we've had multiple failures of the intake valves, exhaust guides and intake guides as well on those heads. So far, all 3 sets that we've installed over the last couple years have been removed due to early failures.

OnPoint

Question for the experts:

If one is going to use new factory intake and exhaust valves in PM guides, do the valve stems need polished, or are they good to go as new? If they need polished, what polishing process is used?

JoesC5

No I haven't. I won't mess with it now, since winter's coming on, but maybe I should run it down to Dallas in the spring and have it checked(and have the heads rebuilt if they show signs of wear, etc while it's there).

Are the failures you have seen been the PRC265 heads with their Ti and SS valves etc.? If so, what kind of mileage did they have on them?

RichieRichZ06

We've witnessed one car have two separate failures in less than 7,500 miles. First time was intake valve guides worn to .030+ in about 6,000 miles and then the second time was a material failure of the valves. It literally pounded the tips of the valves, snapped the hardened tips off and beat them into the top of the springs. The other two cars were both the same failure of the valve and happened in less than 10k miles. They were all PRC 265's with Ti/SS valves. The threads are on here, but got locked.

JoesC5

My Ti intakes do not have the hardened tips but use the OE lash caps from the original GM heads. My engine is as quiet as a church mouse(just like it was with the GM heads.

Michael_D

I'm not an "expert". I do however know that you will want to send the intakes back to Del West and have them re-coated and polished, regardless of guide material used. The Exh stems should be micro polished as well, and then inspected for cracking with die-pen, or mag particle. Or, just replace them.

RamAir972003

Please stay on topic thanks....keep them coming guys...

RamAir972003

Anymore guys...

Josh B.

WCCH

Mileage 37,000

Parts WCCH Stage 2, milled .030, Ti/Mo Intake, OEM Exhaust, bronze guides, PSI springs, Katech seats, Katech Ti retainers OEM seals

Car used for.... putting the hurt on forced induction fanboys

Cam K501

Follow up disassembly and data. Dial bore checked, #4 Intake was toast at .009, all rest were bordering on the .002-.004 zone

Oil change intervals... Second owner, just bought the car, every 5,000 miles?

Type of oil Mobil 1 5w-30

AZDANZ06

Who did them: American Heritage Performance 01/17/2015

Mileage: 27,020

Material: Re-Machined Stock Heads

Parts: AHP PM Guides, Stock Re-Treated Intake Valves, Ferrea F2042P Hollow Stem Exhaust Valves, PSI 1511 Springs, Katech Titanium Retainers.

Car used for: Street

Cam: Stock

Follow up disassembly and data: None Yet, have 684 Miles as of 01/27/2015, will check in 20k more miles

Oil change intervals: 3000 Miles

Type of oil: 0W-40 Mobil One

Unreal

Who did them: PRC285 heads new from TSP, installed myself

Mileage: 18,500 when swapped, just hit 40k miles the other day.

Parts: Out of the box PRC 285s, TI intake, SS exhaust

Car used for: Street/Race. Power for last 20k miles has been between 900-1100+rwhp. Lots of highway pulls to 7200rpm. Sees 20-24psi of boost depending on pulley setup.

Cam: Had a few in it, currently comp 230/246 .650/.650. Had more aggressive and less aggressive cams too.

Follow up disassembly and data: Checked at 38k miles, no issues at all.

Oil change intervals: 2-4k miles.

Type of oil: Had a ton of different oils in it. Normal Pennzoil, Pennzoil Ultra, Brad Penn, Valvoline, and now using Amsoil 10-30W.

Been very happy with the PRC heads and would recommend them for anyone doing a high HP build. If I had to go back I would possibly look at the RHS for the raised runner, or All Pros but they were not out at the time I got my heads.

Chiron

Who did them: Frankenstein Racing Heads (December 2014)

Mileage: 42,000

Material: Re-Machined Stock Heads

Parts: Heads - Stock Intake SS Exhaust, Double Springs, Ported and Milled .030
ARH 1 7/8 Headers
Halltech 105 with Beehive
Ported TB
CAM - (See Below)

Car used for: Street

Cam: 21st Century - 223/235 610 620 115

Follow up disassembly and data: None Yet
Oil change intervals: 3000 Miles

Type of oil: Not Sure Yet

RamAir972003

What power did car make with that cam I have the gt-20 on a 112 lsa

If 21century did it then they use Mobil 1.......

Chiron

The Car made 568 rwhp 496 tq

pewter99

Had mine done at Powertech Performance in St. Pete FL.

Mileage: 82,896

Material: Re machined stock heads

Parts: Ferrea valves and guides, OEM LS7 gasket, ARP head bolts, trunion upgrade

Car used for....daily driver

Cam: stock

Follow up disassembly and data: pending results from Ferrea

Oil change intervals...per DIC

Type of oil: Mobil 1 until now, installed Amsoil

indyspeed

Mileage - less than 6000

Parts - Bronze valve guides, Titanium intake and exhaust values (Katech), and all new valve train parts including push rods (some were GM parts some were Katech)

Use - No track activity

Cam - Stock

Oil change interval - Every year (less than 2000 miles)

oil type - 5w-30

All exhaust valves were bad as reported by WCCH. In fact, Jason from Katech told me they were off the charts bad. Katech did the rest of the installation.

1Sikstik

Mileage: 7500 - 2009 Z06

Shop: Horsepower Sales of Florida

Heads were found to be within spec on a modified LS7

Parts: Existing oem heads & valves blueprinted, port heads, competition multi angle valve job, Clean-up mill surface. SS exh. valves, bronze exh guides, dual springs/titanium retainers

Car used for: weekend fun

Cam: Comp blower cam

Comp Cam trunion kit

Oil change intervals: 2-3000mi

Type of oil: Royal Purple HPS 5w30

Current mileage: 11,900

Have NOT rechecked them yet