cylinder head data

[b rawls]

I am looking for cylinder head data so I can more easily determine flow numbers and velocities for chrysler heads.

When I look in ND I see most intake port volumes for the small blocks listed from 158cc-162 cc. In particular, I calculate the 051 casting as being around 145cc's. Is there a generous porting alowance on some of the heads. This happens on some of the Ford Small block heads. for instance, a particualr 289 head is cast as 125cc's but will check legal up to 155cc's.

my basic question is what are the typical as cast port volumes and max flow numbers for the typical 318/340/360 heads
usually the grocery getter varieties will be in a general port volume region/flow and the more perf oriented may be a tad more.

also for the b/rb engines, what are typical as-cast intake port volumes and max flow numbers in this condition.

buddy rawls www.wighat.com/fcr3

[TD]

At first I didn't know exactly what you were driving at until I went to your website.

I do not have the exact stock configuration numbers, but I do have numbers that are a function of cylinder port volume and intake flow rates at a given cam lift @ 28" Hg.

These numbers were taken from a publication by Hughes Engines and they are as follows:

Small Block

Volume 172cc 245 CFM @ .500"

195cc 265 CFM @ .600"

205cc 295 CFM @ .600"

Big Block

Volume 190cc 250 CFM @ .500"

205cc 300 CFM @ .600"

218cc 330 CFM @ .650"

Hope this helps. What opinions do you form from these values?

[b rawls]

I can only speculate on the big block stuff, because I do not have a good port length value yet. However the small block stuff is hitting dead on with my calculated port lengths, that I got from my ford and chevy models. I still need to measure them, real time, but until then I rely on internet contacts.

those numbers correspond to decently effective port/cross-section relationship. No pro-stock stuff, but not backyard either.
but a basic good seat and bowl design with no significant dead areas in the port.

I really need port volumes for typical as-cast (factory stock) heads. By my calcs a typical 318/360 style runner is going to come out around 145cc. the x-head comes out around 165cc. these are factory casted, not ported runner volumes. Are these assumptions correct?????

The velocity/cross-section relationships are not used to determine a good or bad head, in my case. The relationship is used to calculate an overlap during TDC, based on the port velocity relationships in specified rpm range.

buddy rawls www.wighat.com/fcr3

[paul]

b rawls,I hope the reason you're selling the Pinto is to get a Mopar.We could sure use you in this camp or at least I could. I called Chrysler and got some of the specs on small block head vol. The 273ci heads were 135cc for low performance and 150cc for high.The 340,360 heads were min.160cc.He didn't have specs on the W2 head.The newer high swirl Magnum 318 is 162cc and 170cc for the 360 head.The guy at chrysler was getting a little ticked and I din't have the heart to ask him about the big block heads.You can call them at 248-969-1690[tech.line] I would like to hear what you think about how intake runner length and vol. has on the raming effect right before the intake valve opens if that makes any sense.Can you give any math to help figure this. Your web site really got me thinking.

[b rawls]

I appreciate the time spent calling chrysler on that data. I am really unfamiliar with castings and variations so some of my statements may seem real out of line. As I start to get more data on the heads I will figure this out better.

On the Ram tuning or inertial effects of runner lengths, that is pretty deep subject. there are formaulas out there, but but until I understand how they get around changes and temp effects that happening while the port is flowing, I will just say I do not understand it yet. If you calculate something from a book, but dont understand what the formula is doing, then you really do not know if it calculated correctly or not.

I am not looking to start up in chrysler stuff yet. It is very hard to sell a cobbled up bracket car. If I do a mopar, it will probably a dakota, with a back half treatment.

buddy rawls