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1971 351 Boss Engine Car Shop Manual???
#1
Updated 3/25/2012
My main interest was to build my motor a little cockier than the 351 BOSS, but not much. I wanted to start with it's cam specs and beef it up just a tiny bit from there.

No one has been able to post a Ford published specification for the
351 BOSS Cam. People have posted values, but no one could post a page from a Ford document. People have reported the existence of engineerign specs/documents, but I haven't seen a single page. That means we can only come close to matching the values.

For what it is worth, the 1971 351 BOSS cam is supposed to match the cam for the 1970 302 BOSS. From my 1970 Ford Shop Manual:

1970 302 Boss
Tappet: Mechanical
Lobe Lift: .290*
Theoretical Lift: .477*
Rocker Ratio: 1.60:1*
Duration: Not Listed

Interestingly, my 1971 Ford Shop Manual lists a 302 BOSS/302 HO:

1971 302 Boss Mechanical Tappet
Tappet: Mechanical
Lobe Lift: .290*
Theoretical Lift: .477*
Rocker Ratio: 1.73:1*
Duration: Not Listed

For 1971, a 351C 4v(Boss not listed) shows the following:
Tappet: Hydraulic
Lobe Lift: .247 Intake, .262 Exhaust
Theoretical Lift: .427/.453
Rocker Ratio: 1.73:1
Duration: Not Listed

*There is a dispute regarding the factory numbers. Many sites list the lobe lift at .295. The rocker ratio in all likelihood is a typo for 1970 and should be listed at 1.73. As a result, some say the theoretical lift should be increased to 1.73x.290=.502. However, an "expert" named George Pence believes the .477 number is correct taking into account the fact the Boss utilized a mechanical tappet(He takes into account valve lash with the 1.73 rocker arm ratio, ...but NO ONE is sure the Ford engineers took these same factors into account because 1.60x.290 just happens to matche the .477 published value).

If you are interested, further in this thread are listed part numbers for the original BOSS cams, as well as a SCHNEIDER BOSS CAM. However, at this point, I do not know there are numbers that can be trusted.

I sure would like to have an OEM BOSS cam to measure...$$$$$. Anyone got one on their shelf?

=======================

I have a 1971 OFFICIAL Ford Engine Car Shop Manual, and it has nothing in it about the Boss 351. Does anyone here have one, or is the 351C 4V in the manual I have THE Boss 351?

I have looked online for a Car Shop Manual for the Boss, but didn't find any Ford manuals.

Specifically, I am interested in the SPECIFICATIONS section for the motor. The cam I purchased for my motor is supposed to be a BOSS cam, but I had someone challenge the lift/duration numbers I was using. So I am seeking some clarification.

For what it is worth, I have service manuals for 70, 71 and 73 Fords if anyone ever needs anything.

[Image: 11jmcuc.png]
351C Bold Manners, Brash Attitude
Favorite Teams: Michigan Wolverines and Whoever Is Playing Ohio State.

When I drive past a herd of cows, the cows MOO at me
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#2
Valve Lift: .477" intake and exhaust
Lobe Lift: .290"
Valve Duration/Overlap: 290º/58º intake and exhaust
Exhaust Opens: 86º BBC
Exhaust Closes: 24º ATC
Intake Opens: 34º BTC
Intake Closes: 76º ABC that is what i found looking around , but i also found this "Boss 302 and 351 cams did not offer .477-inch lift; instead, they measured .515 (298 lobe lift x 1.73 rocker ratio). The .477 lift value often associated with the Boss cams is a result of multiplying the .298 lobe lift by the Windsor 1.6 rocker ratio. The 290 degrees of advertised duration resulted in 230 degrees of duration when measured at .050."

Read more: http://www.mustangmonthly.com/techarticl...z1q19bBDkc

[Image: 2zdx09d.png]
Yea,Tho i cruise through the valley of the shadow of rice,I will fear no Turbo,For Torque art with me.Thy rods and crankshaft,they comfort me. Big Grin Robert
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#3
The only "Ford" Document that I am aware of that addresses the specifications and "build up" of the Boss 351 is Ford's "Off Highway Parts" manual which I believe was published in the early '70s.

I do have a copy...there are @10 pages on the Boss 351 application and specifications. This particular book (while now dated) does cover the modifications and specifications of the FEs and the Lima (429/460) motors.

Here is a link for a copy for sale on Ebay.

http://www.ebay.com/itm/1962-70-FORD-MER...9948979360

BT

Do the RIGHT thing.
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#4
In my Ford shop manual, volume 2 engine, they refer to the 302 BOSS or 302 HO.
I did not think they made a Boss 302 in 1971. The manual describes mechanical
tappets and intake valves measuring 2.19 inches.

mike

[Image: 1_11_11_13_11_50_27.png]
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#5
goodnigh;61284 Wrote:In my Ford shop manual, volume 2 engine, they refer to the 302 BOSS or 302 HO.
I did not think they made a Boss 302 in 1971. The manual describes mechanical
tappets and intake valves measuring 2.19 inches.

mike

That is what I have....Without seeing a Ford Shop Manual page, I was wondering if the only difference between the Boss and 4V was mechanical tappets. The shop manual doesn't seem to rule this out, specifying hydraulic tappet leakdown rate.

But, I would have thought the Boss with it's solid lifters would have had a different cam.

What page do you see in the manual regarding solid lifters?

[Image: 11jmcuc.png]
351C Bold Manners, Brash Attitude
Favorite Teams: Michigan Wolverines and Whoever Is Playing Ohio State.

When I drive past a herd of cows, the cows MOO at me
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#6
zgwforum;61291 Wrote:
goodnigh;61284 Wrote:In my Ford shop manual, volume 2 engine, they refer to the 302 BOSS or 302 HO.
I did not think they made a Boss 302 in 1971. The manual describes mechanical
tappets and intake valves measuring 2.19 inches.

mike

That is what I have....Without seeing a Ford Shop Manual page, I was wondering if the only difference between the Boss and 4V was mechanical tappets. The shop manual doesn't seem to rule this out, specifying hydraulic tappet leakdown rate.

But, I would have thought the Boss with it's solid lifters would have had a different cam.

What page do you see in the manual regarding solid lifters?

The page, 21-21-06 of volume 2, describes a mechanical tappet and
not a solid lifter. But there is a valve lash adjustment you make
with the engine at idle. What caught my eye was the 2.19 intake
valves, that is Cleveland size.

mike

[Image: 1_11_11_13_11_50_27.png]
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#7
thundertc64;61272 Wrote:Valve Lift: .477" intake and exhaust
Lobe Lift: .290"
Valve Duration/Overlap: 290º/58º intake and exhaust
Exhaust Opens: 86º BBC
Exhaust Closes: 24º ATC
Intake Opens: 34º BTC
Intake Closes: 76º ABC that is what i found looking around , but i also found this "Boss 302 and 351 cams did not offer .477-inch lift; instead, they measured .515 (298 lobe lift x 1.73 rocker ratio). The .477 lift value often associated with the Boss cams is a result of multiplying the .298 lobe lift by the Windsor 1.6 rocker ratio. The 290 degrees of advertised duration resulted in 230 degrees of duration when measured at .050."

Read more: http://www.mustangmonthly.com/techarticl...z1q19bBDkc
I don't know that I ever heard a Boss 351 motor from the factory. But, based upon my experience, these numbers would produce a pretty lopey idle. From the factory, that would be pretty surprising. I am not saying it didn't happen, I am just expressing my opinion.

It is interesting how the Ford manual is wrong regarding the theoretical lobe loft for the 302 HO(Boss). In my book though, and as you show at the top of your post, the lift is specificed at .290, not the .298 in the article. But then again, once you see a mistake regarding lift, you wonder what numbers are right.

Thanks.

In looking at my Isky cam tables, the duration and lobe lift don't seem to match up.

[Image: 11jmcuc.png]
351C Bold Manners, Brash Attitude
Favorite Teams: Michigan Wolverines and Whoever Is Playing Ohio State.

When I drive past a herd of cows, the cows MOO at me
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#8
zgwforum;61291 Wrote:
goodnigh;61284 Wrote:In my Ford shop manual, volume 2 engine, they refer to the 302 BOSS or 302 HO.
I did not think they made a Boss 302 in 1971. The manual describes mechanical
tappets and intake valves measuring 2.19 inches.

mike

That is what I have....Without seeing a Ford Shop Manual page, I was wondering if the only difference between the Boss and 4V was mechanical tappets. The shop manual doesn't seem to rule this out, specifying hydraulic tappet leakdown rate.

But, I would have thought the Boss with it's solid lifters would have had a different cam.

What page do you see in the manual regarding solid lifters?
ZGW,

The Boss 351 DOES have a different Cam than that found in the 1971 351C 4V and the 1971 and 1972 351CJ.

Boss cam's Part Number is D1ZZ6250B

351CJ for '71 Part Number is D1ZZ6250A

351CJ for 72 Part Number is D2ZZ6250B

351 4V for 71 Part Number is D0AZ6250C

The '71 Boss has a duration of 290/290 while the 71 CJ has a duration of 270/290. The valve lift is also different. The biggest difference between the Boss and the '71 4V/CJ motor is the Boss had quench chambered heads with the adjustable rocker arms.

During the "day", many of us modified our open chambered 351C heads to accept the Boss valve train. It is a pretty simple machining approach and has the added advantage of hardened valve seats.

Hope this helps.

BT

Do the RIGHT thing.
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#9
[/quote]
ZGW,

The Boss 351 DOES have a different Cam than that found in the 1971 351C 4V and the 1971 and 1972 351CJ.

Boss cam's Part Number is D1ZZ6250B

351CJ for '71 Part Number is D1ZZ6250A

351CJ for 72 Part Number is D2ZZ6250B

351 4V for 71 Part Number is D0AZ6250C

The '71 Boss has a duration of 290/290 while the 71 CJ has a duration of 270/290. The valve lift is also different. The biggest difference between the Boss and the '71 4V/CJ motor is the Boss had quench chambered heads with the adjustable rocker arms.

During the "day", many of us modified our open chambered 351C heads to accept the Boss valve train. It is a pretty simple machining approach and has the added advantage of hardened valve seats.

Hope this helps.

BT
[/quote]

I can agree with this....and for what it is worth, a guy named George Pence has calculated the theoretical valve lift of .477 is not a typo. He says the .477 comes from subtracting the valve lash from the lift calculation of 1.73 x .290...

[Image: 11jmcuc.png]
351C Bold Manners, Brash Attitude
Favorite Teams: Michigan Wolverines and Whoever Is Playing Ohio State.

When I drive past a herd of cows, the cows MOO at me
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#10
That would mean .038" valve clearance... That is a ton of lash!

Jeff T.

Low buck, touring style, '73 Convertible "rolling restoration", 351c, 2v heads with a shave and a haircut, Performer intake, Holley 650(ish), roller rockers, screw in studs, guideplates, stainless valves, Duraspark / Motorsports MSD, T-5 conversion. 1-1/8" front, 3/4" rear swaybars KYB shocks and some home brewed subframe connectors. Future plans; JGC steering box, Cobra brakes and... paint, interior, etc.

When I die I want to die like grandpa, peacefully in my sleep... not screaming, like his passenger.

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