Competition 12 V Head Flow Bench Numbers

[Red Stroke]

Jim why . 5" lift? Wouldn't these valves never see that much during operation?

 

[Timebomb]

Low lift #'s are what I look at for low - mid range power befor a big charger lights.

 

[Jim Fulmer]

Don't think you are going to find a street cam with over a . 550 lift, pullers will run more but doubtful on the street.



My head quit flowing more after . 550 lift!



Jim

 

[Forrest Nearing]

Jim why . 5" lift? Wouldn't these valves never see that much during operation?

I think Jim's cam was like . 540" lift.



low lift flow is important because you see it twice!

 

[Timebomb]

low lift flow is important because you see it twice!

You took the words out of my mouth. Many top engine builders will tell you that you should never race a flow bench, They mean they may have a really good flowing head like a 500cfm @ 800 lift but it just wouldnt make the power on the engine. Lots of variables come into play.



I will say it dosnt hurt to spend some time in the bowls on our 5. 9 heads and keep the swirl and unshroud the valve were the seat and the deck are.

 

[Red Stroke]

Well this is PDR Numbers from there website

12 Valve 24 Valve



Intake Exhaust Intake Exhaust

Stock 145 CFM 153 CFM 161 CFM 173 CFM

Stage 1 154 CFM 168 CFM 181 CFM 196 CFM

Stage 2 163 CFM 183 CFM 181 CFM 205 CFM

Stage 3 172 CFM 194 CFM - -



@. 400 of lift



A stage 3 port is around $2500 from them and well over $4000 from Raymac



Here are my cam specs stock vs street cam and valve specs



12 V Stock Cam Lift

· Exhaust . 253 x 1. 5 rocker arm ratio = . 3795

· Intake . 239 x 1. 5 = . 3585



Scheid Street Cam

· Exhaust . 284 x 1. 5 = . 426

· Intake . 263 x 1. 5 = . 3945



Cummins B Intake Valve Specs

· Tip Length 4. 5mm

· Length 5. 08”

· Stem Diameter . 342” 11/32

· Valve Diameter 1. 772”



I am going for a stage 2 if that was easy than biggers always better.

 

[Jim Fulmer]

Odd that the numbers you have and the ones I have are so different. I had the specs of 423 intake and 473 exhaust for a stock cam ground on a 102 centerline.



I would have a tough time buying and installing a cam with less that a . 500 lift, just don't see the gain for the $ crossover.



Jim

 

[Timebomb]

Very good info.....



Well another thing Ive allways wonderd was what the other specs of those cams were duration and overlap those two things I would think would be the most usefull to know with a forced induction engine.

 

[ThrottleJockey]

Maybe we can take two DuraMax heads and cut one cylinder off each one and weld them together for our straight sixes,

 

[Red Stroke]

Jim I was under the understanding that anything with more lift than the street cam would require flycut pistons resulting in a lowered compression ratio, and for a streetable motor I don't want to lower my compression ratio.



Also stock intakes seat off at 30 deg and exhaust at 45 deg. For a N/A motor you get more flow out of a 30 deg valve angle than 45. Raymac says they get more flow out of 45 deg than 30. Seems everyone else is using intakes as exhaust valves and changing to 30 deg for both? Hmm



The change can be made for $27. 00 a piece for the new 45 deg valves vs stock intake 30 deg for $12

 

[Jim Fulmer]

Mine are at 45 degrees also and had 20k on them when they were looked at in December and they were still fine. I know a stage 2 cam is real close to . 500 lift (or so I was told) and it doesn't require a cut piston, a stage 3 does.



Mine are cut either . 050 or . 060, head is milled . 008 and compression is around 15. 5.



Jim

 

[Red Stroke]

Jim sounds like you did your homework on your head, thanks for the info.

I am going with stock 30 deg intakes in both places and going to try for piers stage 3 numbers. I should have some flow bench info next week.

 

[Timebomb]

Pro Stock cars run 45deg. valves so that tells you something right there.

 

[Red Stroke]

My porting guy called me today and said that I have one exhaust seat cracked and another crack from the intake seat to the injector hole.

This head came off a 200K 160hp motor bone stock.

 

[JTEdieselram]

I know this post is old now, but I got my head back from Haisley last wensday, and was not happy with the port work at all I asked for stage 3, was charged $700. 00, and recieved stage 1/2, it literly looked like a 12 year old kid with a cartridge roll spend 30 minutes on the whole head. The exhause ports were the only thing that been touched, and they were only ported in for about the 1st inch, the rest of the port, the part of the port that matters was never touched. needless to say I was extreamly ******, and felt like I had been had, but the rest of the head, Ti retainers, springs, and machine work for the fire rings was very nice. I waited over two months for the head so I was'nt about to send it back and start over. Patty explained to me that the work was done at anouther shop, and that it "must have been a new guy", and that she had not personally seen the head. She is going to work a deal out with me on some other parts, but buyers beware. I thought a well know shop would provide a nice port job especially for the $$$ I spent, but they did not. I think porting a head should be done by yourself to achieve the job that you want. I can port heads, it is just a hassel, I guess I learned my lesson.

 

[Red Stroke]

Sounds like a pain in the *****, haisleys will take care of you they are good people only if you can get a hold of them on the phone!



Well to revive my post. My guy has my intakes to a stage two now without knocking off the extra material on the intake guides, side opposite exhaust in pics. Installed the 30 deg intakes in the ex and ported wich increased flow in low and high lift (0, to . 400) but went turbulent in the mid range (. 200) lift. He is going to keep going and stop at a PDR stage 3 #s.



Jim whos came were you running?



I have been researching cams and none of scheids streetable cams are in the . 500 lift range. They are changing the duration around but not getting into the . 500 of lift. The cam I changed to has . 450" lift int and ex and needs . 080 and . 060" flycuts respectively.

 

[Jim Fulmer]

Jim whos came were you running?

Still runnning the stock cam, can't say I will stay with it for good! As I edge up on 650 with #2 and 850 on Gas it going to be hard for me to think a cam will help that much, but it may! Now if someone forked up a cam I would do the swap for R&D.



Jim

 

[JTEdieselram]

I can say that the truck is back together with the Haisley head, 13mm II pump/dragon flow injectors, BIG twins, and of corse the F1 helix 3 camshaft. Runs like a raped ape! can't really say what made the biggest difference because I did all the work at the same time except for the turbos. EGT's are manageable, and the truck is really REALLY driveable (in vallet mode) cam/headwork/huge injectors/pump did not effect it one bit, I think I will continue to drive this truck every day again! Jim, did you ever install the F1 cam you talked about doing?

 

[Bobcat698]

For those of you that want to take a LOT of material out of the bowls, BE CAREFUL!
These heads definitely are not consistent... We broke through a water jacket on the #6 exhaust port on my new head. . We took a punch and it took a LOT of pounding on the other exhaust port bowl wall areas and only broke through on the #5 bowl.

 

[Jim Fulmer]

Jim, did you ever install the F1 cam you talked about doing?

Nope, still on a borrowed stock cam.



Jim