[dci]

Good points!! Pushrods no doubt will need to be 9/16 tapered if there is room.


Don Johnston
DCI MOTORSPORTS INC.
330-850-5050 shop
330-628-3354 cell
Designer of the DCI Tiger Heads and the NEW DCI Ram Air 5 Heads !!!!!

[john marcella]

Originally Posted by dci

Good points!! Pushrods no doubt will need to be 9/16 tapered if there is room.


Don Johnston
DCI MOTORSPORTS INC.
330-850-5050 shop
330-628-3354 cell
Designer of the DCI Tiger Heads and the NEW DCI Ram Air 5 Heads !!!!!

A friend that run PS bike and after spintron testing has told me that the port needs to cater to the push rod, Make room! But then again he runs a 2.700+ valve at 9800 so because of weight and valve acceleration ,he has big spring press, you may not need that kind of press. There are many variables.

Just for reference I am at 284@50 206@200 .543 lobe 1.9 rocker and total weight of valve, retainers , locks and lash cap is 119g. I am stable through 9200 no prob. IMO you will need to get more like 210+ at .200 with a 1.9-1 and better yet 2.0-1. That im sure would be enough area to insure you could make the 2.3 with a Pontiac with that kind of area. JMO I could wrong.

[Stan Weiss]

Originally Posted by john marcella

A friend that run PS bike and after spintron testing has told me that the port needs to cater to the push rod, Make room! But then again he runs a 2.700+ valve at 9800 so because of weight and valve acceleration ,he has big spring press, you may not need that kind of press. There are many variables.

Just for reference I am at 284@50 206@200 .543 lobe 1.9 rocker and total weight of valve, retainers , locks and lash cap is 119g. I am stable through 9200 no prob. IMO you will need to get more like 210+ at .200 with a 1.9-1 and better yet 2.0-1. That im sure would be enough area to insure you could make the 2.3 with a Pontiac with that kind of area. JMO I could wrong.

John,
I believe George Bryce as of the end '13 was running 2.7" with a .600" lobe with 2.0:1 rockers intake and 2.0" with a .600" lobe with 1.85:1 rockers exhaust. But remember that they are 2 cylinders and if it was a v8 it would be around 640 ci, yet they turn over 10,000 RPM. Note they are running a 5.1xx" bore. Since last fall George PMed me the HP and torque, lets just say it is over 2.3 HP per and under 2.4 HP per.

Stan

[john marcella]

Originally Posted by Stan Weiss

John,
I believe George Bryce as of the end '13 was running 2.7" with a .600" lobe with 2.0:1 rockers intake and 2.0" with a .600" lobe with 1.85:1 rockers exhaust. But remember that they are 2 cylinders and if it was a v8 it would be around 640 ci, yet they turn over 10,000 RPM. Note they are running a 5.1xx" bore. Since last fall George PMed me the HP and torque, lets just say it is over 2.3 HP per and under 2.4 HP per.

Stan

Trust me Stan, I know every last thing about George's cyl heads.