Anyone who has had a car, pickup or
Hot Rod with a Y-Block in it knows that you just have to have a
set of ECZ-G heads if you want to make any power, NOT TRUE!
Although if you are making a race engine the "G" heads
or 113 castings are preferred, if you are just running on the
street you can make decent power with a set of old truck heads.
That's right! all those C1TE, C1AE and C0AE castings that
everyone just passes over are very good heads with a little
work.
To start with they have 76, 72 and 75cc chambers respectively,
the "G" heads have 69cc chambers but with a little
milling you can get the volume down and all these heads are
"Posted". Bonus! Rule of thumb is .005" off the
surface 1cc reduction so take .020" off and that's 4cc's.
Now for the fun part. I've been using 1.85" and 1.6" SI valves meant for a sbc +.200" length.
Stock chamber
I cut the exhaust first since the stock valves are slightly smaller than the 1.6" SI valves. The intakes however are.200" to
gain.
After cutting the seat
The next step is to cut the excess meat in the bowl left after
cutting the bigger seat.
Now all that's left is to grind the rough edges out and make a
smooth radius from the port to the chamber. You can polish this
as much as you like but the biggest gain is from cleaning it out
not making it shiny.
I use stainless swirl polished valves and you do need to cut the
giudes down about 1/8" so the retainers wont hit with
.500" lift.
You can do this on other heads not just Y-blocks just make sure
you have enough material before you cut, you don't want to hit
water.
These heads are going on a 292 that will power our LSR Unibody
for some testing, although this engine is not likely to break
any records (158 mph is the D/PP class record at Elmo) I do hope
to better 130. I'll keep you posted.
Update 2012: These heads running on a fairly stock 292 in my Unibody pickup at Bonneville in 2011 did three back to back runs at 120 mph. With a change of heads on the salt to ECZ-G heads that were formerly on Charlie Burns "Yellow Brick" 258ci Y-Block the Uni improved it's speed to 127mph. this will give a good comparison on performance. Keep in mind that the "G" heads were "worked over" extensively, I believe (refer to dyno chart below) that the reworked C1TE heads perform on the same level, or better, than stock "G" heads.
http://www.jalopyjournal.com/forum/s...d.php?t=531700
Dyno cylinder head test by Ted Eaton
Here are the ‘very summarized’ results of how
sixteen different pairs of heads recently performed on the 312
dyno mule. A pair of the ECZ-C’s and C1TE-D’s was a before and
after milling comparison which jumps the number of published tests
to eighteen. The same carburetor, intake, headers, timing, and
valve lash was used in all these tests. The camshaft is a Crower
Monarch with 0.450” lift, 238°@0.050”, ground on 110° lobe
centers, and installed 2° advanced or 108° intake lobe
centerline. The intake manifold is an unported Mummert dual plane
paired up with a 750cfm vacuum secondary Holley sitting atop a
2” oval opening carb spacer. 1.6:1 roller rockers are being used
for all tests. Total ignition timing is 38° BTDC. For these
particular test results, the headers are used with mufflers which
helps to keep this particular information set comparable. The
degree or amount of porting when performed on the heads is not
listed on this particular chart.
Cylinder
Head
|
Peak
HP
|
Peak
Torque
|
Comp
Ratio
|
Ported
|
Mummert Aluminum
|
377
|
368
|
9.8:1
|
Yes
|
Mummert Aluminum
|
354
|
356
|
9.8:1
|
No
|
113
|
333
|
350
|
9.2:1
|
Yes
|
*G
|
328
|
350
|
9.4:1
|
Yes
|
G
|
324
|
349
|
10.6:1
|
Yes
|
G
|
304
|
337
|
9.6:1
|
Yes
|
G
|
302
|
337
|
9.2:1
|
Yes
|
G - stock
|
290
|
344
|
9.2:1
|
No
|
471
|
296
|
332
|
8.3:1
|
Yes
|
ECZ-C – stock
|
288
|
336
|
9.0:1
|
No
|
ECZ-C – stock
|
280
|
335
|
8.6:1
|
No
|
ECZ-C – stock
|
273
|
330
|
8.1:1
|
No
|
*ECZ-C after milling
|
295
|
339
|
9.0:1
|
Yes
|
*ECZ-C before milling
|
290
|
334
|
8.4:1
|
Yes
|
*C1TE-D after milling
|
297
|
337
|
9.0:1
|
Yes
|
*C1TE-D before milling
|
295
|
335
|
8.4:1
|
Yes
|
COAE-A - stock
|
283
|
332
|
8.7:1
|
No
|
COAE-A w/larger valves
|
273
|
328
|
8.9:1
|
No
|
A special thanks
goes out to those of you that donated heads, shipping, and/or
funds to make all this happen. For those of you that sent funds
without any name(s) on the envelopes, an extra thanks also. This
testing has generated a plethora of information which is being put
together for a series of articles for the Y-Block Magazine.
Lorena,
Texas (South of Waco)
*Heads by Tim McMaster
|