Opinions on Pontiac cams

Bonnewagon

Geezer
Sep 18, 2009
7,744
113
Queens, NY
OK then. What you need to remember is that the displacement affects how the cam acts. The exact same cam that acts obnoxious in a 350 would be a snoozer in a 455. That is why I said most of those cam charts are generally intended for the 389/400 engine as it is in the middle. So when I used the Crane HMV260 in a 1976 350, it was very peppy, grumpy idle, and acted like it had an attitude. The same cam in my 1977 400 TA was milder with a smooth idle. It seemed like it should do more, but the short duration held it back. Yet in the 350 it was perfect. Meanwhile it was advertised as an RV/off road/mileage cam. But in a 350 it was a lot of cam. That is why I advised against the 068 in a 350. It may roar in a 400 bit I think it would kill a 350. I also would never use the Crane HMV278 cam in a 350. It was cranky in a 400, a 350 would never like it. Those are the only two aftermarket cams I ever tried. I have used lots of two and four barrel Pontiac cams over the years and I like the 066/067 the best. It was the base cam for the average GTO 389/400 engines. Remember the factory gave you power that still idled well and didn't overheat and should last 100k miles. It should work well in a 350. They are getting hard to find though and you would probably need to get similar lift and duration numbers from an aftermarket cam. I think Melling makes a blueprint series of old cams. Then there is the arguments over using the same lift/duration or adding more to the exhaust side on a Pontiac. I agree with that- more exhaust bias. Yeah, I get the "455 it" complaints too but I even like the 301 so what does that say?
 
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spidereyes455

G-Body Guru
Thread starter
Mar 6, 2013
591
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Northeastern PA
That HMV 260 sounds intriguing but I can't seem to find it in a google search. Mabey they don't make it anymore? Would you happen to know the specs or have an old copy of the cam card so I could see if I can find the same or similar grind from a different manufacturer?
 

Bonnewagon

Geezer
Sep 18, 2009
7,744
113
Queens, NY
Camshaft - Hydraulic Flat Tappet - Lift 0.427 / 0.454 in - Duration 260 / 272 (advertised) - 112 LSA - 1200 / 5000 RPM And I got that from SEARS!?! https://www.sears.com/crane-hyd-flat-tap-cam-0.427-0.454-in-lift/p-A012222905 Don't worry it's a Chevy item they made that grind for Fords too. I chose it for the lift because the Pontiac stock springs can't take much more than .450" lift and this was right on the money. I didn't need a high revving cam either. Like I said, Crane or Pontiac Blueprint Series are getting hard to find. This Summit is close.

Summit Racing SUM-1794 - Summit Racing® Camshafts


Camshaft, Hydraulic Flat Tappet, Advertised Duration 272/272, Lift .454/.454, Pontiac, V8, Each
 

spidereyes455

G-Body Guru
Thread starter
Mar 6, 2013
591
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carnutjw

Master Mechanic
Supporting Member
Sep 17, 2017
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Oct 14, 2008
6,801
113
Melville,Saskatchewan
This is interesting. I wonder if Pontiac's small bore has to do with how these cams act?
 
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Bonnewagon

Geezer
Sep 18, 2009
7,744
113
Queens, NY
Jim that Lunati is almost a carbon copy. Even though the int/ex lift is the same, the .454" is right on the money. And I too like a bit more exhaust duration. FWIW when I had that Crane cam in the 350 I was using the Pontiac factory HO exhaust manifolds. Breathing was not a problem.
 
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spidereyes455

G-Body Guru
Thread starter
Mar 6, 2013
591
93
Northeastern PA
I hadn't noticed before that the cam card lifts int and exh lift both at .454. Looking at the summit listing and right on the Lunati website both list it as .432 int and .454 exh.
 

spidereyes455

G-Body Guru
Thread starter
Mar 6, 2013
591
93
Northeastern PA
This is interesting. I wonder if Pontiac's small bore has to do with how these cams act?
I've been wondering that myself. Since no one looks down their noses at a sbc 350 or even a olds 350. Both of those seem to be routinely built with 220 or more duration @.050 on the intake side without a second thought. But the general consensus seems to be that much duration is too much on a Poncho 350.
 
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