<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: VintageMusclecar</div><div class="ubbcode-body">Time for another quick update:
As I mentioned in
this post of the 496 dyno thread, I was on the hunt for another pair of rectangle port closed chamber heads before the 496 had even cooled off from the last dyno pull.
Within 2 weeks, our own Joe Smith came through with a good pair of 840 casting cores.
I had originally intended to send them to the same porter who updated the 462 heads on the 302 project, but he politely declined as he's trying to get away from working on iron castings (esp. big block Chevy units) in the interest of sparing himself from further back aggravations. Can't say that I blame him.
At any rate, I asked him who he would recommend I send the heads out to, and without hesitation he advised Chad Speier of
Speier Racing Heads.
After discussing my goals with Chad, he agreed to take on the project. I just received the news that Chad finally had the chance to get started on them, and he posted two sneak peek pics on the Chevelle site (and on his Facebook page as well)
A <span style="font-style: italic">little</span> chamber work:
Getting started on the intake ports (click the link, the pic won't embed here for some reason):
https://scontent-iad.xx.fbcdn.net/hphoto...amp;oe=559F4566
More info as it becomes available. </div></div>
Heads are done. [img]<<GRAEMLIN_URL>>/naughty.gif[/img]
Flowed on a 4.310 fixture. 1 7/8 pipe:
I'll format some numbers later for comparison's sake, but suffice it to say Chad knocked this one outt'a the park. [img]<<GRAEMLIN_URL>>/biggthumpup.gif[/img]
*edit* Here are the comparison numbers to an unmodified set of 840 heads with 2.19/1.72 valves to Chad's work:
Speier Racing 840 heads vs. unmodified
--Intake#2---before/after--Intake#4--before/after---Exhaust before/after
----.200-----133.9--151.7--------------134.3--147.5------------100.5--123.4
----.300-----208.5--218.9--------------209.5--215.8------------124.4--164.5
----.400-----234.3--264.8--------------256.5--276.5------------145.9--187.9
----.500-----257.8--292.8--------------272.4--307.6------------162.0--210.7
----.600-----274.1--322.3--------------292.7--332.0------------177.6--231.3
----.700-----271.8--324.8--------------291.7--342.8------------177.3--249.8
----.800-----273.6--340.0--------------292.1--354.0------------178.2--260.4