Valve overlap

[FireSale]

Read the Duration section of this link. It explains a bit more about the effects of duration and why cam grinders use 0.050 lift. It's a bit too long to post.

http://www.austincc.edu/wkibbe/camtheory.htm

Also this from the HotRod network:
http://www.hotrod.com/articles/ccrp-...amshaft-power/

Also: I'm going to just keep my AFR 1399 heads with the 1.9/1.6 valves that they come with. No fit issues with the BOSS302 block. If I declare the car for SS/CS I can run the Combo legally. Aluminum heads any valve size 10.5 lbs/cid. The index sucks O2 (10.30) but I have thrown t he book at my car over the Winter.

[SSDiv6]

Originally Posted by FireSale

Read the Duration section of this link. It explains a bit more about the effects of duration and why cam grinders use 0.050 lift. It's a bit too long to post.

http://www.austincc.edu/wkibbe/camtheory.htm

Also this from the HotRod network:
http://www.hotrod.com/articles/ccrp-...amshaft-power/

Also: I'm going to just keep my AFR 1399 heads with the 1.9/1.6 valves that they come with. No fit issues with the BOSS302 block. If I declare the car for SS/CS I can run the Combo legally. Aluminum heads any valve size 10.5 lbs/cid. The index sucks O2 (10.30) but I have thrown t he book at my car over the Winter.

Sorry Dale, you cannot run aluminum cylinder heads in SS/CS class, only cast iron, inline/wedge heads only.

[FireSale]

Originally Posted by SSDiv6

Sorry Dale, you cannot run aluminum cylinder heads in SS/CS class, only cast iron, inline/wedge heads only.

OK. I read this revision as "Aluminum heads OK. No billet in modified classes except CS"

2017 revision:
Aftermarket aluminum cylinder heads permitted (no billet) except in CS.

I'll take the car to ETI in March and see. I'm beginning to not care any more.

Back to camshafts.

[SSDiv6]

Originally Posted by FireSale

OK. I read this revision as "Aluminum heads OK. No billet in modified classes except CS"

2017 revision:
Aftermarket aluminum cylinder heads permitted (no billet) except in CS.

I'll take the car to ETI in March and see. I'm beginning to not care any more.

Back to camshafts.

Dale,
The rule can be confusing.
What the rule change should say is that any aftermarket aluminum head, except billet heads are allowed.
Still, SS/CS class is NHRA approved cast iron cylinder heads only.

Prior to the current rule, it was required to run approved cylinder heads that had an OEM part number.

As applicable to your Mustang, would be the Ford N351 cast iron cylinder head casting.The N351 head, as cast, just with port matching, will outflow the AFR 165 heads by a mile.

[Adger Smith]

Comp Cams Chart
http://www.compcams.com/Pages/413/ca...ion-angle.aspx
Might give you some added info

[west coast]

Adger I have been using that page a lot of great info there.The issue i am having now i think is in the black science of designing cams that is not printed. like when to open and close valves during the stroke, how much lift during overlap, lots of variables roller versus flat tappet cam, engine stroke. I am looking to improve what i have, I have identified an issue over a year ago and looking to solve it. So understanding valve overlap and a standard on what lift and if it is tappet or valve is important with the issue I have.

Dale one other thing about the new BOSS block is it has different size head bolts also.

[SSDiv6]

Originally Posted by west coast

Adger I have been using that page a lot of great info there.The issue i am having now i think is in the black science of designing cams that is not printed. like when to open and close valves during the stroke, how much lift during overlap, lots of variables roller versus flat tappet cam, engine stroke. I am looking to improve what i have, I have identified an issue over a year ago and looking to solve it. So understanding valve overlap and a standard on what lift and if it is tappet or valve is important with the issue I have.

Dale one other thing about the new BOSS block is it has different size head bolts also.

James,

If you want make your life easier, I recommend this base software package:

http://www.controlledinduction.com/djrc.html

If you want to spend hours analyzing data, although spendy, this would be the software to use:

http://www.motionsoftware.com/Dynomation5.htm