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Mail From: Dan Jones <(email redacted)>

Chuck,

Here's some more info on Crower's CHP series of 5.0 roller cams. I never
did find out why (or if) the CHP found it necessary to swap cams. Maybe
I'll call their tech line and ask. The info I have indicates Crower's
5.0 cams are not smog legal. MM&FF did a couple of artices on the CHP
cams they used in a project car. They found the 15511 cam had too much
overlap for their Dart headed stock compression 5.0, so they had Crower
whip up a single pattern custom grind (212, 0.531, 116) for the August
1992 article. They shaved 0.035" off the heads and went with a wider
lobe separation angle to keep dynamic compression ratio up.

Even though the Crower cams don't have an EO, they checked emissions.
Here's how they stacked up:

cam HC CO2 CO O2
ppm % % %

stock 29 14.7 0.01 given as 1/4% but may have been typo (1.4%)
15511 340 13.9 1.01 1.4
custom 23 15.0 0.01 1.5

The 15511 cam seems to be a chameleon. The July 1992 MM&FF article used
this cam but quoted different specs (278/288, 218/222, 0.467/0.488, 114)
than Crower. I think (couldn't find his posting but I had these numbers
scribbled down) Brian Kelley showed different specs as well (282/286,
218/222, 0.467/0.486, 114). JBA's catalog shows yet another set of specs
(278/282, 217/222, 0.467/0.488, 114). I don't know if Crower has refined
this cam a few times or if these are just typos.

MM&FF ran into a problem which may be of interest to list members. During
the cam swap, they replaced the factory timing chain set with an after-
market true roller timing chain set. It turns out the late model timing
gears have an integral spacer that the older flat tappet cams do not have.
Putting an old timing gear meant for a flat tappet cam on a new roller
cam leaves play on nose of the roller cam. Without the spacer, the bolt
and washer that is supposed to push the gear firmly on the nose of the
cam doesn't make contact, so the gear walks back and forth on the cam
nose until the shear loading breaks the dowl pin. This can cause big
problems (bent valves, pushrods, and dowel pin). They ultimately used
the SVO M-6268-B302 billet steel cam sprocket. There's also M-6268-A302
(full roller timing set with cast iron cam sprocket).

Cheers,
Dan Jones

Crower Cams
- -----------

Cam# Kit Adv Dur .05 Dur Lift 1.6 Lift 1.7 LC LobeSep RPM Range

Stock ----- 272/272 211/211 0.437/0.437 115
15510 84560 275/275 212/212 0.531/0.531 114 1500-5500
15511 84560 278/282 218/224 0.468/0.486 0.497/0.516 114 1800-6000
15512 84562 282/286 222/228 0.496/0.512 112 2100-6500
15513 84562 288/298 228/234 0.512/0.531 112 2400-7000
15514 84562 298/304 234/240 0.534/0.545 110 2700-7500
15515 84562 300/310 236/242 0.524/0.529 110 3000-8000


Notes: Stock indicates specs given in Crower catalog for stock Ford 5.0 cam.
MM&FF article has different factory specs: (211, 0.433, 116)
Crower recommends re-using stock roller lifters.
JBA recommends 1.7 ratio rockers on cam 15511.

Order 800-222-2267
Tech 619-422-1191
Fax 619-422-9067