Ok,I have been wondering this for a while.Hope these fit into this forum First question .How is the angle of the head determined.Like a 23* head.Is that refering to the angle of the valve to the top of the piston,or runner angle to the valve or something else?Advantages and disadvantages of the different degrees?Second one regarding flow numbers.Is the flow determined from one valve?Or all four(say intake)at a time?Thanks in advance for all replies.

 

the 23*, 18*, 14* etc is the valve angle in relation to the piston. the more shallow degree of the valve angle the more flow you end up with in general thats why until the ls1 shallow angles were only used in racing applications and never in a production sbc. thats big part of why an ls1 with ported heads is a force to be reckoned with. some ls6 heads ported out by people who are at the top of the game can flow nearly 360cfm. while lt1 castings like to peak in the mid to high 200's. the other thing is the more shallow the angle the longer the intake runner generally is too. a ported ls1 head that "works" will probably be almost 230cc's while a ported lt1 casting will generally be about 200cc's. once again the difference being not that the cross section is so much larger but that the port is longer. the disadvantage barring the ls1 is that 99% of 18* heads require shaft mounted rockers and a solid roller cam with offset lifters... not exactly daily driver friendly. they also require pistons with the propper "fly cuts" in them. recently an 18* head cam out that can use standard 23* hardware and a hydrolic cam.

as for the flow numbers thats usually one port from what i gather. and while cfm and head flow is important there are A TON of other things to consider when it makes power. the cfm that a head can put through is just an indication to the porter that they're getting the shape they're looking for in the head. the reason you hear so much about flow is that its easier to sell a head that flows 270cfm than it is a head that flows 260.

hope that helped an i didnt get too far off base.

 

Thanks you covered it all nicely.

 

A disadvantage to the pocketbook, yes, but not a disadvantage where valvetrain stability is concerned. That makes it very daily driver friendly in my book.
Plus, many of the good 23* heads out there require an offset, but most people have forgotten that you can run stud rockers on those heads.... the AFR 215 for example.
Brodix has an 18* head that accepts standard 23* valvetrain and flows 320+ cfm out of the box.... volume is up there though.

-Mindgame

 

What about the heads you have?? whats your setup?? your car is N/A right??

LMK

Thanks

 

Check out these threads that are discussing his setup-
First Thread Second Thread
But lets keep the discussion in this thread on the topic of the original question.
Thanks.

 

Highlander,

Let's not get on a tangent in this thread. Here's a thread in LT1 tech where I've been asked to spill the beans....
http://web.camaross.com/forums/showt...hreadid=137966

Ask your questions there and I'll try to answer as best as I can..... I would like to keep a few things to myself though.

-Mindgame

 

I am watching those threads already.. sorry