wildcamaro

iTrader: (15)

I would think H/c/I is MUCH cheaper than a turbo build unless you can fab your own stuff, although when crunching the numbers a supercharger becomes very affordable when looking at h/c/i....

Personally I prefer all motor, but either of the 3 ways will bet the same results, although boost will provide a higher ceiling

AceBoogie

My HCI cost about $2500 with parts purchased from on here.

TFS 215cnc heads
MS4 cam
LS6 intake
Harland Sharp Roller Rockers
Double roller timing chain

Also, I love the combo mentioned above. I haven't taken it to the track yet, but I'm sure it is good for some high 10s

Exidous

iTrader: (11)

I don't mean they are bad or anything. I got 90whp out of the 5.3's, 228r and a fast 102 compared to the stock cam and 241's. You can't beat the 5.3's for the price.

Those aftermarket castings really are the way to go if you aren't on a tight budget.

Trevor @ Texas Speed & Perf.

iTrader: (3)

For what you're looking to do, there's no doubt that the PRC 227's will do the job well! We ran them on our shop '98 Z28 in 2009 as a heads/cam setup with a stock LS1 short-block, and we ran a best of 9.66. This was at the NMCA LSx Shootout. Our PRC 227's were designed for exactly what you're looking to do. It's a max-effort set of cylinder heads that work incredibly well on the smaller bore engines. With the 227cc intake runner size, they maintain excellent port velocity! You can also take advantage of additional compression since they come standard with a 62cc chamber size. All of the PRC aftermarket casting cylinder heads also come STANDARD with our PRC EHT .675" dual valve spring kit with titanium retainers, and they also all have the 6-bolt provisions in place. So, if you ever decide to build an LSx or RHS short-block, you could certainly carry these cylinder heads over to the new setup. With that said, if you build a really big bore engine (i.e. 4.125" or more), you'd benefit quite a bit from the PRC LS7 cylinder heads. All of our cylinder heads work excellent out of the box, and we have never had to "massage" the ports by hand for better flow. Our shop car was running out-of-the-box PRC 227's. We ran our PRC 215's and MS4 cam in 2008 at the LSx Shootout, and the car ran a 9.82 @ 134 MPH.


Feel free to give us a call with any questions or concerns. We have plenty of PRC cylinder heads in stock, so if you order early enough in the day your order can ship the same day in most cases! Each set of the PRC heads will be setup specific to your combination. We know exact clearances with all of our camshafts, so we know just how much we can mill the cylinder heads so you can have the most compression possible without having to worry about piston-to-valve clearance issues!



Trevor
Texas Speed & Performance

fly boy_1

iTrader: (4)

How far can those 227's be milled (to what CC rather) and retain stock PTV clearance of say a stock 241 casting with a stock thickness gasket? Did you guys ever release your as cast 220's?

Trevor @ Texas Speed & Perf.

iTrader: (3)

You can run right at a 60cc chamber size with our 227's and still retain stock p-to-v clearance. As for the as-cast cylinder heads, we have released our PRC 225cc as-cast cylinder heads. They are in stock and ready to ship!

http://www.texas-speed.com/p-3515-pr...ral-heads.aspx

Let us know if you have any additional questions or concerns.

Thanks!

Trevor
Texas Speed & Performance

JakeFusion

iTrader: (7)

Trevor, with the EHT springs are stock rockers okay with ~470lbs open pressure? Also, do the heads accept a 3/8" pushrod without modification?

95ONE

iTrader: (1)

Trevor, what was the cars race weight?

Trevor @ Texas Speed & Perf.

iTrader: (3)

The stock rocker arm bodies will work fine, but we do recommend the Comp Cams trunion upgrade if you plan to use the stock rocker bodies. As for the pushrods, the heads are setup to accept the standard 5/16" diameter. We did not want to open up the hole and give up some air flow due to having to reshape the port from the larger opening. If someone needs to open the pushrod holes up, it can be done. Just be VERY careful when doing so! FYI, we were spinning 8,000 RPM through the traps last year with 5/16" pushrods when we ran our 9.65. Yes, it was still stock pistons, rods, and crank! We did have a set of ARP rod bolts in place, but I'd still recommend that you wear a cup for that kind of RPM with a stock short-block.

The race weight was 2,880 lb. with me in it.

Let me know if anyone has any other questions.

Thanks!

Trevor
Texas Speed & Performance

dr_whigham

iTrader: (49)

I've personally never heard of ANYONE recommending a stock rocker for open spring pressures in excess of 400#s.

Tainted

iTrader: (9)

so whats the largest pushrod you can fit into these heads without having to change anything?

Trevor @ Texas Speed & Perf.

iTrader: (3)

I didn't recommend a stock rocker. I recommend the stock rocker arm BODY with the Comp Cams trunion kit. Big difference. We have sold over 250 of the Comp Cams trunion kits this year. They're a very popular upgrade. The stock rocker body has a significant weight advantage over most of the aftermarket rocker arms. We were running stock GM rocker bodies with the Comp trunion kit when we ran the 9.82. We had to pull the aftermarket rockers off after we ran into valve float issues on the engine dyno at 6,800 RPM. We replaced the rockers and could spin 7,200 without any issues. I don't recommend them because I've been told. I recommend because we've tested them. We also have a lot of customers doing the same without issue.

JakeFusion

iTrader: (7)

The stock rocker is the way to go for valvetrain stability due to the weight. I don't think anyone would argue that point.

The question I have and I believe whigham is also asking is around the 470 number and the rocker arm body.

I understand the need for that sort of open pressure due to the large 2.6" stainless intake valve, but doesn't that put a lot of stress on the GM aluminum rocker body? I don't know. Just asking for clarification purposes.

If the stress is on the stock trunion and that fails, then that'd be one thing. But I think with most rocker failures, stock or aftermarket, the actual aluminum body breaks, usually at the pushrod cup.

dr_whigham

iTrader: (49)

Trevor, I'm not getting into a pissing contest with you or your 9 second run.

But the fact of the matter is, trunion upgrade or not, you run stock rockers on a spring with more than 400# of open pressure, and you get valve scrub. You chew into the rockers' tips, wear down the valve tip, and wear out valve guides. All within 10 to 15 thousand miles.

For a purpose built drag car; a non issue. For a street car, this becomes a problem.

Agree with your statement about the cheaper roller rockers though.

AutoCruzer

I would suggest being careful about the heads. Heads typically make gains above 3500 rpm and while you are not likely to lose anything down low with a careful selection, you may make gains that are only negligible without a good intake as well. You could easily end up out of 2-3000 dollars before seeing anything worth talking about.

I am no expert, but typically I see heads gain above 3500 rpm and intakes from 4000-4500 rpm on. I see them do their best work with a combination of a carefully chosen intake, heads and cam. Usually this is a 2500-3000 dollar affair so choose wisely.

speedtigger

iTrader: (16)

GM Rockers are steel and very strong.

LS1T56FTW

iTrader: (3)

I have dyno proof to show the before and after on my setup what a properly built HCI setup can do.

First dyno:
Mods: Full exhaust, LS6 intake/P.P. TB
338.6WHP/353.8WTQ
Trapped 86MPH in the 1/8th on this setup

Second Dyno:
Mods: PRC 5.3 heads, 228/232 Cam, (Same intake/exhaust as before), 25% UD pulley, Monster Stage 2 with 18lb flywheel
470.4WHP/418.6WTQ
Trapped 98MPH in the 1/8th with this setup

I have videos and slips of both pulls on here somewhere. Car is currently full weight.

Quick math shows you that I picked up 131.8WHP and 64.8WTQ.

Trevor @ Texas Speed & Perf.

iTrader: (3)

Glad to hear it. I never intended it to be a pissing contest. I'm just clarifying. We have been selling our EHT spring kit for a few years now, and the vast majority of customers running them are doing so with stock rockers. But, if we're going to use 400 lb. as the magic number, you don't want to see how many .650" kits we've sold with customers using stock rockers. They have 450 lb. of open pressure. We could weaken the spring to under 400 lb., but the more aggressive ramp rates on the market now need springs that can properly handle them. The old "gold" spring that has under 400 lb. of open pressure also loses install height after 15,000 miles. That's why we haven't used them in a few years. We were seeing long-term problems with them, but others continue to use them to this day. The overwhelming majority of our customers drive their cars everyday. I'm not sure what you have seen, but we are not seeing this issue with our customers. That's just a fact. Trust me when I say if there is an issue we will quickly hear about it! This thread is getting derailed from its original purpose, so please PM or e-mail me at trevor@texas-speed.com if you'd like to further discuss the stock vs. aftermarket rockers.

FYI, the stock rocker arms are steel, not aluminum. We set our castings up to accommodate the 5/16" diameter pushrods because that's what the overwhelming majority use and need. We did not want to sacrifice some flow for the very few that would require a larger diameter pushrod. We built the cylinder heads to appeal to the masses.

Let me know if you have any other questions.

Thanks!

Trevor
Texas Speed & Performance

JakeFusion

iTrader: (7)

Thanks, Trevor. PRC 227 is an appealing set of heads. I haven't seen many dynos of it. Do you have any?

Trevor @ Texas Speed & Perf.

iTrader: (3)

yes sir! I will pull the graph from our engine dyno computer and get it posted up today.



Trevor
Texas Speed & Performance