Heh, really? That's no fun.... Any idea on what you hope it'll make once you get the problem resolved? You were well over 700 last time you dyno'd weren't you?


Later
Chuck

 

Ya know, I'm gonna sound like a *** (what's new?), but that should have read 1300 HP

Good grief, you'd get spanked like a frat boy's monkey with only 1KHP in Pro Stock

While we're on the subject, the '01 Pro Stock champ, Randy Walker, will run Race Prep motors this year

470 RWHP heads/cam LS1's have been commonplace for a while? Hmmmm......., maybe I need to come out of hibernation. Since all the big dog Texans are calling BS on such claims from certain shops, me thought that mark was somewhat of a novelty.

But, can't fault your opinion, Phil. Looks like I'm in the minority since I actually agree that not only is checking out someone's work by a third party a good idea, but should be common practice Just wanted to point out that based on this shops track record and credentials, it seems unlikely they would pull a page out of the old "PP" trick book But hey, I've been wrong plenty of times before

 

I'll flow them again at SAM... since I start school there next month Not that I feel I need to, just to prove a point. Race Prep is a force to be reckoned with.


Later
Chuck

 

I'm with Phil.

He's right, and as I said before the low and mid lift numbers are not up to par with the rest of that head. The people who do the porting have nothing to do with what he said, they can be professionals, and do good work, but those numbers just look plain odd for a 23 deg head.

I don't think that Phil has any personal feelings against for these heads and numbers. Why when a professional comes on here to help out does he get his head chewed off, it seems that stoping misinformation is a good thing, except on this board. You don't see this kind of stuff on LS1tech.com at all.

I look at world class heads and the flow numbers associated with them all the time. These numbers seem odd, they really do. Plug them into a excell spreasheet and look at the flow curve. That curve would be VooDoo to me, the high lift flow with no mid lift to support it seems worthless.

Here are a couple of charts to look at to see what we mean about flow curves.
http://www.weldtech.com/graphics/GM_HUT921.gif
http://www.weldtech.com/graphics/BrodixTrack1Chevy.gif
http://www.weldtech.com/graphics/HVH231_10X.gif
http://www.weldtech.com/graphics/Jones240_10RI.gif

The first one being a 18 Deg Head and the last 3 being a 23 deg head.

The 2nd one is a favorite of mine and on a 350 would make TQ numbers that would make the 396 cube guys jealous. Seriously, I've made 540 ft lbs out of a 6.0L engine, it's about 30 cubes less than a 396 and I've never seen a LT1 396 make that kind of TQ.

BTW the 470rwhp LS1 heads/cam cars are ZO6's with the LS6 castings, it's much easier to do that in that car with that set of heads and driveline. Try and do that with LS1 castings, and a 12bolt in a F-body your not gonna see 470rwhp doing that.

Just my thouhgts, If you think I'm wrong. Your gonna need alot of proof and a army, because the things I have seen in my work say other wise. It's just our (Phil and I) opinion that this is odd and someone needs to look into it. Take it for what you take it for.

Bret

BTW when you are at SAM ask the Cylinder Head Prof what he thinks of those flow numbers, I have a feeling he will say something is up.

 

Nope.

647 was the most they saw on any pull, and on the pull that Mark sent me numbers for, 640.8 before the dip @ 6,600, and 636.7 after the dip @ 7,400 rpm, so there's some more power in between, even on the base maps, but I'd hate to guess how much. The last dyno session was in April last year, so we're rolling on 10 months now, waiting for parts (and modifications) to eliminate the damn Opti-spark.

 

Do you need a plane ticket to B&B in Redding to be present the next time they dyno my 396? You can talk with Mark in person and ask about my Voodoo-brand (tm) heads... and tell them what they're doing wrong.

The arrogance of "professionals" who think that something they haven't seen or didn't have a hand in can't exist? You tell me.

 

Well, maybe the thing I didn't make clear enough was the fact that we built these heads with one very important purpose in mind. Air speed. I simply posted the flow numbers because even they are still very impressive. But the heart of these beasts is the speed at which the air moves. So yes, maybe the flow numbers aren't all that impressive... but I'm going to guess that if you put my heads up against your heads on the port flow analyzer you're going to find out rather quickly that these things really are some killer heads. I mean, even you admited that heads this size usually only get to the 31x mark. So you know full well that if these heads really do flow this well, that they are also REALLY moving the air fast. And you know that's a really important factor when building a killer street head So maybe, just maybe Race Prep achieved the ultimate goal of maximum velocity combined with awesome port flow?
As for my low lift numbers... I could send you my cam specs if you really must know. Then you could see that my cam spends little to no time at all in low lift. They open quick, stay open, then shut quick. That's why the high lift numbers are so good, and the low lift numbers aren't as impressive.


Later
Chuck

 

BTW. Valvetrain consists of the following if you also wanted to know that...

Del West titanium retainers
Super seven degree locks
Isky tool room springs
Ferrea valves (2.08/1.60)
Jesel Sportsman shaft mount rocker assembly


Later
Chuck

 

Chucky,

Maybe you can get Bryan to register here and chime in Not to start a pissing match, but I for one always learn a thing or two when professionals shoot ideas and opinions off eachother

BTW, how did you learn of their operation? Most folks that frequent UBB's opt for the generic mail order types of heads.

 

Yeah, it would be cool to have Bryan or Joe on the board, but I know they're just too busy to even think about it. It took them about 3 days after they printed the spec sheets just to fax them to me.... So they're very preoccupied. If you have any questions you can email them to raceprepinc@aol.com.
Yeah, I was trying to think yesterday how I found out about them... And I think it was from Bob (4drLT4), off an impalass forum if I remember correctly. I had talked to lots of people about doing heads for me.... GTP, Lingenfelter, CNC, Mark Montalvo, ARE, Combination, Hans Feustal, etc... But Race Prep stood out tall to me as being the guys who really knew their stuff. Their credentials prove that. If anybody differs with my opinion that's fine. I chose to go with Race Prep because I believed in them. Others will go with other companies because they believe in them. But the numbers should prove that these guys know what they're doing. I mean, for goodness sake, my peak flow numbers are 1.1 cfm less than Jimlab's huge raised runners (and that was at .800 lift on his... mine were only tested up to .650). If you guys question the quality of Race Prep's work, I question your ability to think.


Later
Chuck

 

Yeah they are busy... I'm still waiting for my 383 to be built... *sigh* I'd rather have them work and make $$ than post on boards.

 

Oh are you Bob's friend? What kind of setup are you having them put together for you?

Later
Chuck

 

yeah I know Bob... Theya re putting together a 383 w/ forged Scat rotating assy with JE/SRP pistons assembled and ready to go. They are gonna have a custom cam ground based on the head specs. I already had a set of Combination stage 2 heads. Otherwise, I woulda gone with a set ported by them. I could have sold the heads but I was already tapped as it is.... I'm not looking to become the fastest, just wanted a good reliable stroker that will handle some juice too. Looking to put down 400RWHP/450RWTQ NA....

Joe and Bryan are great guys with a superb shop that reeks of cleanliness. Their work or "dirty" area is even spotless. I saw Randy Walker's heads there one day... looked like you could stuff a tennis ball thru the intake ports!! I met and chatting with Randy on a different day I was there... very nice guy. His car is unbelievable too......

 

Ahh, you went with CM heads? I was considering going with them too, but after I talked to Bryan at Race Prep, the difference was night and day. Bryan just flat out knew what he was talking about. The guy at CM (forget what his name was?) was trying to tell me my setup was too wild and that it would run terrible unless I put in some hogged out 220's with intake runners sizing up to around 225 and flowing the same numbers Bryan and Joe did with puney little 213cc runners He tried to tell me that velocity was out of the question and that all they would be able to do to compliment my setup would be huge runners and lots of flow. Bryan on the other hand was very confident that what I already had going was going to work great, and knew exactly what they needed to do to the heads to make my setup work perfect. I think they did an excellent job, and I can't wait to see how this baby performs on the dyno once we get it all put together
Sounds like you'll still have a real nice runnin car though. I'm sure you'll be happy with it. Eventually you can always swap heads out if you want Good luck to ya, keep me updated! I wanna hear how things turn out....


Later
Chuck

 

I guess I didn't realize those links I posted didn't work... For anyone who would like to view the charts click here then click on "heads"....


Later
Chuck