George difference between ur boss cam and CJ cam?

George difference between ur boss cam and CJ cam?

Joined: March 8th, 2012, 8:27 pm

August 1st, 2012, 6:46 pm #1

Hey george just wanted to here the differences between your cj cam and boss cam?

As you know my car is 68 fastback t5 five speed and 3.89 or 4.10 gears.

Combo is

10.1 compression
Torker intake or blue thunder
Cc 4v heads with ss valves
Msd atomic efi

I wanted a solid flat..., can anyone of these cams be a solid flat cam?

Also on a side note the msd says up to 250 duration @050 but I think 260@050 should be fine given the wide separation

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Joined: January 1st, 1970, 12:00 am

August 1st, 2012, 6:54 pm #2

link:
http://www.351c.net/home-2/cleveland-pa ... aft-specs/

blizz

(don't get too attached to that link I'm still moving furniture around the new house)

351C.net, not just any old internet car forum,
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Joined: October 1st, 2004, 8:05 pm

August 1st, 2012, 7:44 pm #3

Hey george just wanted to here the differences between your cj cam and boss cam?

As you know my car is 68 fastback t5 five speed and 3.89 or 4.10 gears.

Combo is

10.1 compression
Torker intake or blue thunder
Cc 4v heads with ss valves
Msd atomic efi

I wanted a solid flat..., can anyone of these cams be a solid flat cam?

Also on a side note the msd says up to 250 duration @050 but I think 260@050 should be fine given the wide separation
I've never spec'd the Cobra Jet cam as a solid lifter cam ... doing so doesn't make sense to me. It would be possible I guess. Here's both specs as hydraulic flat tappet cams:

Cobra Jet camshaft
Grinder: Bullet Cams
Intake: Lobe #H275/318
Exhaust: Lobe #H285/324
-----------------------------
275°/285° advertised duration
280° average duration
Exhaust valve opening = 80° BBDC
Intake valve opening = 25° BTDC
50° overlap
Exhaust valve closing = 25° ATDC
Intake valve closing = 70° ABDC
------------------------------
225°/235° duration @ 0.050
0.550"/0.560" valve lift
115° lobe separation angle (camshaft degrees)
Intake lobe mathematic centerline = 112.5° ATDC
Exhaust lobe mathematic centerline = 117.5° BTDC
___________________________________________________

Boss camshaft
Grinder: Bullet Cams
Intake: Lobe #H285/324
Exhaust: Lobe #H295/324
-----------------------------
285°/295° advertised duration
290° average duration
Exhaust valve opening = 85° BBDC
Intake valve opening = 30° BTDC
60° overlap
Exhaust valve closing = 30° ATDC
Intake valve closing = 75° ABDC
------------------------------
235°/245° duration @ 0.050
0.560"/0.560" valve lift
115° lobe separation angle (camshaft degrees)
Intake lobe mathematic centerline = 112.5° ATDC
Exhaust lobe mathematic centerline = 117.5° BTDC

Bottom line - Compared to the Boss spec the Cobra Jet spec has less overlap, less intake duration, the exhaust valve opens a little later, the intake valve closes a little sooner.

A motor with the Cobra Jet cam installed will idle with a nice muscle car burble to the exhaust note, but no lope. The power band is shifted a little to the left (lower rpm), the lower rpm power is a little stronger, the upper rpm pull signs off a little sooner. There's more intake manifold vacuum. Combine the Cobra Jet spec cam with a Blue Thunder manifold having a full height plenum divider, quench chamber heads, and a properly calibrated ignition and the low speed power of a 351C 4V is just as strong as any motor. It feels refined (mellow?) like a factory motor, but the top end rush is still there ... which is the characterisitic that distinguishes the 351C 4V from all other motors.

When I was younger I preferred the Boss spec in my car's motor, when I got older I stuck a CJ cam in the motor.

The CJ spec makes a better cam for a daily driver and for older - slower guys like me in general. If you want to use a single plane manifold for the looks, the Cobra Jet spec is a better match for a street motor with a single plane manifold because manifold vacuum will be better and the powerband may hopefully extend a little further into the low rpm range.



-G
____________________________________________________________

Pantera Photos | 351C Historic Information | 351C Technical Information



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Joined: March 8th, 2012, 8:27 pm

August 1st, 2012, 9:03 pm #4

I think I'm going to go With the solid flat boss cam for my daily driver I'm young and like to go fast still lol. The gears should compensate for down low anyway.

The atomic efi I'm thinking of buying by msd says no cams over 250 duration@050 but it isn't much bigger in a solid and with the wide lobe separation I think it would still work... After all it's only 10degrees bigger.
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Joined: May 20th, 2005, 4:48 pm

August 1st, 2012, 9:34 pm #5

A difference of 10° is a big difference.

I think you need to do a little more research before you settle on a cam. The cams that George listed in his post up above would work really well, but you're totally going the wrong direction with the 250° and 260° cams. A wide LSA doesn't work miracles and a deep rearend gear can only make up for so much.

You're going to end up driving a turd as a daily driver if you're not careful.

Brent Lykins
B2 Motorsports, LLC






Last edited by blykins on August 1st, 2012, 9:44 pm, edited 1 time in total.
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Joined: March 8th, 2012, 8:27 pm

August 1st, 2012, 10:02 pm #6

His solid version of the boss cam as george calls it is 250/260@050.....And says is just like a boss 351.... Just alittle more...


He claims off line performance till way up in the rpm band?
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Joined: May 20th, 2005, 4:48 pm

August 1st, 2012, 10:35 pm #7

But his cams that he has listed today, with the .050" durations in the 220's and 230's would be much more up your alley.



Brent Lykins
B2 Motorsports, LLC






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Joined: March 8th, 2012, 8:27 pm

August 1st, 2012, 10:53 pm #8

Sounds good. I just want to get it right the first time...Two different trains of thought and in up in the air... I do know the boss 351 was a running box stock... Running what high 13s stock...

Hoping to hit 325rwhp at least and be able to drive it everyday.

Either going with georges boss 351 solid... Or a another small solid flat cam...
So much great knowleedge on this board.
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Joined: May 20th, 2005, 4:48 pm

August 1st, 2012, 11:29 pm #9

And you can be very docile at that level. No big cam required.

Brent Lykins
B2 Motorsports, LLC






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Joined: March 8th, 2012, 8:27 pm

August 1st, 2012, 11:36 pm #10

Ya 325 rear horsepower is my low number...but don't wanna be disappointed

I wanna hopefully make 340-350rwhp with matching torque....

What's that 425-440 at the crank?
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