82sportcoupe

did anyone see the article in the latest super chevy mag about the DM w/ the sr torquers? some of you may know that they had 416 casting heads on the motor w/ 62cc chambers (i think) and they replaced the stock heads w/ the s/r's (67cc i think) and they lost torque and horsepower over the entire range. probably alot of the power loss was due to the drop in compression, but i just thought that was rather odd. i figured theyd do better than that. anyone else have anymore details on that test?

jimmy_mac

I don't have any more details but I was pretty shocked when I read that article. I didn't expect a huge improvement but to see a loss was crazy.

82sportcoupe

at one point, i was thinking of getting these heads, im sorta glad i didnt cuz i would have been highly once i found out that a cheaper ported and polished/shaved stock pair of heads made more power.

i guess stock replacement means simply that.

F-BIRD'88

Although the S/R's are a nice, quality made casting, the port flow
of the as delivered out of the box head is only as good as a stock head. Not surprised at all that a set of 461's would make more power. (I haven't read the article so I'm assuming the 461 have been tweeked a little at least).
Given equal preperation, the S/R's would be right up there too.

These heads have good potential but need porting to really work.

iroc22

They're excellent heads with quality parts. As mentioned above, they have great potential with extra thick walls for porting. They're decent outta the box but can be improved on in many places.

Plus going from a 58cc chamber to 67cc, would give a massive drop in compression, resulting in a huge power loss. I havent seen the article, but was the engine a 305? 416's are 305 heads and I'm just curious to what engine they were testing these heads with.

82sportcoupe

im not sure the cubes of the motor in the article. yeah, the compression ratio is what killed them. i reread my last post and maybe it seemed to me that maybe i was being a little overdramatic. has anyone ported and polished a set of the s/r torquers and got flow numbers for them? im a little curious as how much more flow you can get out of these heads compared to out of the box.

Shagwell

416's are 305 heads - 62cc head, but need some hogging for a 350 to breath well. 461's are 350 closed chambers(approx 62cc) but have no accessory bolt holes. - The S/R Torquers make for a decent head with a good amount of port work. - just my $.02.

F-BIRD'88

Chevy Dart SR Torquer Flowtest Reports


Test Performed on my Superflow SF-600 @ 28"



TESTS INT1 INT2 EXH1 EXH2
LIFT CFM CFM CFM CFM
.050" 30.1 30.1 23.1 26.0
.100" 61.7 61.8 45.8 51.2
.150" 90.8 92.5 79.3 79.8
.200" 120.5 126.2 101.7 102.2
.250" 147.8 152.5 110.0 126.5
.300" 168.5 175.9 110.7 140.3
.350" 184.7 192.2 112.2 144.4
.400" 193.6 202.6 112.2 146.9
.450" 199.5 208.8 112.2 149.2
.500" 195.1 207.0 112.2 151.5






Tested using a 3/8" clay radius on the intake port and nothing on the exhaust port.
Used a 4.00" cylinder bore size.
Test INT1 is the Dart SR torquer intake port with the as supplied valve (2.02") and valve grind.
Test INT2 is the same port as INT1 with a minor bowl blend done.
Test EXH1 is the as supplied exhaust port with the as supplied valve (1.60").
Test EXH2 is the same port and valve as EXH1 with minor bowl blending.

I got this off the net. It's not my test. But is from a reliable source. This is stock and a very minor quicky pocket blend job.

These heads can be ported to 245 ot 250 cfm by any one with the patience. 260/270cfm is a professional job. Ex port can go over 200 cfm.

F-BIRD'88

Here is another flow test. this is after a full basic port job.
You can do this.
valve size is 2.02" x1.60"
050" .100" .150" .200" .250" .300" .400" .500" .600" .650"
Intake 63.4 88.4 120. 147.6 174.4 197.9 236.0 244.1 249.6 250.3
Exhaust 42.5 56.8 90.8 118.4 153.3 167.1 181.7 189.8 195.6 199.2