Thoughts on this cam shaft for 302 4 speed '68

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xr7g428
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Thoughts on this cam shaft for 302 4 speed '68

#1

Post by xr7g428 »

The engine the basket case '68 XR7 4 speed I bought last summer was rebuilt before I got it and it has never been fired.
The build was supposed to be a mild hop up, nothing radical just a little sumpthin'

Flat tappet hydraulic Cam Shaft specs are:
Duration @.050 218 degrees intake and exhaust
Advertised Duration 284 degrees intake and exhaust
Valve lift .461 Intake and Exhaust
Lobe separation Intake: 107 degrees, Exhaust 119 degrees

This uses the 351 firing order 13726545

Heads were "cleaned up" but other wise stock.
Bill Basore, Editor / Publisher
Legendary Cougar Magazine
Currently in the Cat House
'67 XR7 GT 390 4 speed, AC, AM FM, Lime Frost Green
'68 XR7-G 428CJ C6, Tilt-Away, AM, Black Cherry
'68 XR7-G 390 4 speed, Sunroof, Cardinal Red
'68 XR7 GT-E 427 C6 AM Cardinal Red
'68 XR7 resto mod 351W, soon to be AOD, Black Cherry

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BossElim69
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Re: Thoughts on this cam shaft for 302 4 speed '68

#2

Post by BossElim69 »

Yes, pretty mild cam but matched up good with the stock cyl heads. I think it looks just fine. The only concern I have if I’m seeing your numbers right is the 107 degrees lobe separation is on the low side and will effect the amount of vacuum the engine makes. Should give you some pretty good torque in the lower RPM range.
Brian Carpenter, President CATS classic Cougar club
67 Cougar road course racer
67 Cougar project car
67 Cougar GT
68 XR7-G trailer queen restoration.
68 Restomod
69 Boss 302 Eliminator
69 XR7 390 survivor
69 XR7 428CJ 4spd
69 standard convertible
70 Boss 302 Mustang
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Royce
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Re: Thoughts on this cam shaft for 302 4 speed '68

#3

Post by Royce »

Those must be love Center line angles. Lobe seoeration on a camshaft is a single number. This cam is so mild the LSA must be something like 115 degrees. What’s the part number and manufacturer?
1968 GT-E XR-7 W code 427 Augusta Green / Saddle
1968 XR-7 R code 428CJ Ram Air Red / Black
1910 Model T Ford Touring Red / Black
1914 Model T Touring Maroon / Black
1915 Model T Ford Touring Black / Black
1917 Model T Ford Torpedo Runabout Green / Black
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Royce
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Re: Thoughts on this cam shaft for 302 4 speed '68

#4

Post by Royce »

Test
1968 GT-E XR-7 W code 427 Augusta Green / Saddle
1968 XR-7 R code 428CJ Ram Air Red / Black
1910 Model T Ford Touring Red / Black
1914 Model T Touring Maroon / Black
1915 Model T Ford Touring Black / Black
1917 Model T Ford Torpedo Runabout Green / Black
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robert campbell
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Re: Thoughts on this cam shaft for 302 4 speed '68

#5

Post by robert campbell »

In almost all cases the lower the centerline separation means more overlap and a high performance cam for higher RPM use. The greater the separation reduces overlap and is a mild cam for low RPM and higher torque at low RPM for basic street use. There must be a misprint on the lobe centerline numbers. A separation of 218 degrees is not in the realm of normal separation. 107 is usually a lumpy cam with poor idle characteristics, and a lobe separation of 114 is more of a stock cam. The use of roller technology (steeper ramps) can produce wide duration with larger lobe separation than flat tappet cams. The best of both worlds.

Rob

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xr7g428
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Re: Thoughts on this cam shaft for 302 4 speed '68

#6

Post by xr7g428 »

Cam Lobe separation should have read:

Intake 107 degrees Exhaust 119 degrees

I think it is an Engine Pro Racing MC4225. The specs are hand written and when I look those up this is the match I find.
Bill Basore, Editor / Publisher
Legendary Cougar Magazine
Currently in the Cat House
'67 XR7 GT 390 4 speed, AC, AM FM, Lime Frost Green
'68 XR7-G 428CJ C6, Tilt-Away, AM, Black Cherry
'68 XR7-G 390 4 speed, Sunroof, Cardinal Red
'68 XR7 GT-E 427 C6 AM Cardinal Red
'68 XR7 resto mod 351W, soon to be AOD, Black Cherry

robert campbell
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Re: Thoughts on this cam shaft for 302 4 speed '68

#7

Post by robert campbell »

You got me on this one. I have never seen two figures for lobe separation before. From my experience lobe separations is the degrees between the centerline of an intake lobe and an exhaust lobe. Duration can differ and lift, of course, can differ, but lobe separation is one figure in my experience as Royce said.

This is a new one on me. but I am confident that the smaller the amount of degrees between the exhaust and intake centerline produces more "overlap" which is the amount of degrees that the intake and the exhaust valve are open at the same time. More overlap equals less vacuum and a lumpy idle that is usually needs to be faster. Not desirable with power brakes and automatic transmissions with stock convertors.

Anyway, I am ready to learn!!

Rob

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