340 cfm LS1 castings
340 cfm LS1 castings Has anybody had any work done by this shop www.race-prep.com? I have never heard of anybody getting 340 cfm from ls1 castings before. The heads are expensive though 3000.00. Just wondering if there are any happy costomers out there I am considering having them build me a stroker and porting my ls1 heads?
On The Tree
Joined: Oct 2003
Posts: 128
Likes: 0
Linear Velocity had their LS1 heads on top of his 388 all bore. He got something like 511 horsepower with a non-gigantor cam and 12:1 compression. I'm sure he will chime in sometime if he sees this thread. He is the only one I have ever read about with their heads.
Moderator
Joined: Apr 2002
Posts: 814
Likes: 0
From: Murrieta
My LQ9 heads from race-prep flowed 342/237 @ .600" lift through 2.08/1.60 valves. On a stock shortblock with a 230/236 cam, mac headers, and stock MAF and TB the car made 450rwhp/410rwtq. The heads were ported over two years ago. I think they're heads are flowing even better now. I would definitely recommend checking them out.
Be sure to have them flow tested independently once you receive them. I bought a set of heads from them a couple years ago, before I started my shop, and they were about 50 cfm down from what their flow sheet claimed... Check out the last half of this thread to read more about my experience with them.
Chuck
Chuck
Race Prep is probably one of the best cylinder hea porters out there, I would definitely recommend them, Joe is a great guy and took the time to answer a lot of my questions regarding the heads. As for Chuck, I've seen enough independent reviews of your situation and it looks like there was a misunderstanding on your part so please stop posting a link to your tired thread everytime someone is asking about their LS1 cylinder heads, even though you have LT1 heads.
I'll be the first to admit that's a tired old thread. But there's nothing wrong with a second opinion. The fact that they were LT1 heads has nothing to do with claimed flow numbers vs. actual flow numbers and actual dyno numbers. They flowed mid 280 cfm, and made exactly what a mid 280 cfm head should've made on the dyno (560 fwhp). No confusion on my part. 
Chuck
Chuck
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FormerVendor
Joined: Nov 2001
Posts: 3,065
Likes: 6
From: Houston, Tx.
I think overall Joe and Brian are good guys and maybe their LSx heads are better now since every shop has their good and bad times. At that time they claimed almost the same flow numbers for their LTx heads as the LSx heads and the LTx stuff just doesn't have the flow of the 15 degree LSx heads, valve size to valve size, not now, not ever.
Chuck had a bad experience with those heads and I was there first hand since I told him right off the bat I didn't believe those numbers and sure enough they did not flow anywhere near 330 cfm. These boards are for people's experiences and Chuck has had plenty. In fact he was a great promoter of Race Prep until that time. Just setting the record straight since maybe 20 different guys on here (LS1Tech.com) saw what those particular heads flowed and they saw the initial flowsheet that came with the heads as well. All of those guys are on this board and were at the school or gradualted from there including many in pro racing if you want any other indepedent opinions. One is a head porter for Joe Gibbs Racing now and he also jokes about those particular heads.
Chuck had a bad experience with those heads and I was there first hand since I told him right off the bat I didn't believe those numbers and sure enough they did not flow anywhere near 330 cfm. These boards are for people's experiences and Chuck has had plenty. In fact he was a great promoter of Race Prep until that time. Just setting the record straight since maybe 20 different guys on here (LS1Tech.com) saw what those particular heads flowed and they saw the initial flowsheet that came with the heads as well. All of those guys are on this board and were at the school or gradualted from there including many in pro racing if you want any other indepedent opinions. One is a head porter for Joe Gibbs Racing now and he also jokes about those particular heads.
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