81 350
Thread Starter
Safety Car
Joined: Apr 2004
Posts: 3,997
Likes: 1
From: WAY DEEP INSIDE AMERICO,YES YOU LIVE HERE TO!! TX
Originally Posted by Dalannex
Anybody know what the stock cylinder head chamber and runner sizes are on the 1981 350?
-Justin
-Justin
lets here it for the 82 heads also 
Instructor
Joined: Dec 2004
Posts: 216
Likes: 1
From: Lapeer Michigan
They are 76cc's.
Here are 2 sites with the flow & valve size.
http://users.erols.com/srweiss/tablehdc.htm#tabtop
http://www.mortec.com/castnum.htm
Yes the port matching is worth the little work.
Here are 2 sites with the flow & valve size.
http://users.erols.com/srweiss/tablehdc.htm#tabtop
http://www.mortec.com/castnum.htm
Yes the port matching is worth the little work.
Safety Car
Joined: Mar 2000
Posts: 4,078
Likes: 27
From: Northeast South Dakota
My sportsman II's are 72 cc. So, if I would put the stock heads off of my 81' motor on my current motor (10.25:1 CR) and my sportsman II's on my stock 81' 350 I would end up with higher compression on the stock 81' motor and lower compression on my current motor, correct? And, from looking at the links above it appears as though the Sportman II's don't flow much better than the stock heads. Is this correct?
-Justin
-Justin
Thread Starter
Safety Car
Joined: Apr 2004
Posts: 3,997
Likes: 1
From: WAY DEEP INSIDE AMERICO,YES YOU LIVE HERE TO!! TX
Originally Posted by Dalannex
My sportsman II's are 72 cc. So, if I would put the stock heads off of my 81' motor on my current motor (10.25:1 CR) and my sportsman II's on my stock 81' 350 I would end up with higher compression on the stock 81' motor and lower compression on my current motor, correct?
-Justin
-Justin
Yes you arte correct
Thread Starter
Safety Car
Joined: Apr 2004
Posts: 3,997
Likes: 1
From: WAY DEEP INSIDE AMERICO,YES YOU LIVE HERE TO!! TX
Originally Posted by Dalannex
And, from looking at the links above it appears as though the Sportman II's don't flow much better than the stock heads. Is this correct?
-Justin
-Justin
. I am going to port match the stealth manifoldand the stock heads and see If there is a difference
