[428RA4]

Originally Posted by 65nss4spdGTO

Without speaking for Don, the factory style pushrod insert was an added obstruction to the port. With the ability to cast this requirement into the head, it allows for greater control in directing the air through the port. By casting this into the head, the port shape can be made to compliment the obstruction almost dividing the ports into two segments. Similar concepts are used on 4 valve cylinder heads.

Calvin Hill
Hill Performance
708-250-7420

Calvin -

Thanks for your thoughts. Though it may be a better control for airflow, I'm wondering if this design would limit your ability to port the heads. After all, it's now twice as hard to smooth out surfaces.

[65nss4spdGTO]

Originally Posted by 428RA4

Calvin -

Thanks for your thoughts. Though it may be a better control for airflow, I'm wondering if this design would limit your ability to port the heads. After all, it's now twice as hard to smooth out surfaces.

No limitation at all.

Nothing a good carbide and some machining can't change IF you wanted to go back to the factory design.

As far as porting, using the right size tools will do the trick.

Calvin Hill
Hill Performance
708-250-7420

[Baron Von Zeppelin]

They turned out some nice castings !

Cast-In pushrod/port divider concept sounds real interesting too.

Don't tell anybody i asked ... but will BigBlok Chevy headers match the exhaust port layout ? Just wondering if their plentiful ready made headers could be incorporated.

[Baron Von Zeppelin]

Never mind
i googled some pictures of those headers .

woulda sure been convenient if they woulda been close

[428RA4]

Knock yourself out...

http://www.ebay.com/itm/1969-1970-GT...3&cmd=ViewItem