Joined: Wed Aug 11 2010, 10:15AM
Location: E WA
Posts: 1230
Hi:
I finally bought a set of 440 Source stealth heads. I my opinion they look really good.
I decided to measure the volume of the combustion chambers since I did not believe that they could be anywhere near as bad as the 80 cc +/- 5% that is claimed by 440 Source which is +/- 4 cc or 76 cc to 84 cc.
On one head I measured 80.6; 81.7; 82.0; 81.6 cc
On the other head I measured 82.2; 81.6; 82.5; 82.5 cc average is 82.2 cc
On the first head I removed some material to get the 80.6 cc chamber to 81.6 cc
So now that head is 81.6; 81.7; 82.0; 81.6 cc average is 81.75 cc.
The chamber volumes are well under +/- 1% of each other but perhaps more significant is that the average volume is really more like 82 cc than 80 cc as claimed.
I have no idea how other heads compare to this, factory or after market. There is going to be some error in the measurements that I made but I would guess no more that a couple of tenths of a cc. I did use a 50 mL Class A burett (accurate to 0.02 mL) and a Lexan cover plate bolted down using the head bolt locations.
I had a pair that were cnc'd by modern cylinder head(outstanding work).I sold them to a buddy and got a chance to look at them in the machine shop the other day.Have the guides checked on yours.The ones on this pair were in sad shape and several had to be replaced after a short run time.