Pontiac - Street No question too basic here!

          
 
 
Thread Tools Display Modes
Prev Previous Post   Next Post Next
  #40  
Old 05-31-2011, 09:43 PM
77 TRASHCAN's Avatar
77 TRASHCAN 77 TRASHCAN is offline
Ultimate Warrior
 
Join Date: Oct 2008
Location: 31May2013 Temporary home to the world's widest (that we know of) tornado. Lord, NO more Please...
Posts: 6,750
Default

Another note...
One of my Pontiac fellow enthusiast's told me, and I read the same in Jim Hand's book, that essentially ALL 67 and up "D" port heads have the same port shape/volume. Jim Hand says they are all around 153 cc's. Just for curiosity I measured the same port that I cc'd the chamber on. it was 150.5 cc's. The difference in most of those heads is the chambers and valve size. The deeper chambers changes the port alignment.

I have a 77 (from my car) and a 78 400. I might re-work the 17's, install 2.11 and 1.77 valves in them, give them a Jim Hand port job, and use them on a 400 (maybe) I'll have to evaluate the 400's first.

I think that the small valve (my opinion) 350's from 68-70 and all about the same chamber size as I measured, then in 71 the chambers got way bigger to knock the comp ratio down to 7.6:1 My motor book lists the 68 and 69 small valve 350's as 9.2:1.
Not knowing the deck height of a stock 350, it could even be less. I'm guessing at 8.25:1 w/ the 8.35 cc chambers using Jim Hand's compression ratio guide for the popular Pontiac engines on page 74 of his book. I found a head/compression ratio chart @ Wallace Racing, they list the 68 350's as 8.6:1, crap at least they are closer that my Motor Book.

One thing that Jim Hands tells you in his book, is to check every head for it's chamber volume, never to take it for granted...Thanks again Jim Hand!!!

One good thing I did uncover, I cc'd a chamber on a 6X-4 head, it came in @ 93 cc's. I was glad about that one, I've heard that some -4's can be quite a bit more...

__________________
1977 Black Trans Am 180 HP Auto, essentially base model T/A.
I'm the original owner, purchased May 7, 1977.

Shut it off
Shut it off
Buddy, I just shut your Prius down...
 


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 12:26 PM.

 

About Us

The PY Online Forums is the largest online gathering of Pontiac enthusiasts anywhere in the world. Founded in 1991, it was also the first online forum for people to gather and talk about their Pontiacs. Since then, it has become the mecca of Pontiac technical data and knowledge that no other place can surpass.

 




Copyright © 2017