1971 351 Boss Engine Car Shop Manual???

[Wolverine]

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.

 

[thundertc64]

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/techarticles/mump_1001_boss_351_block_buildup/viewall.html#ixzz1q19bBDkc

 

[cobra3073]

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-MERCURY-OFF-HIGHWAY-FACTORY-HIGH-PERFORMANCE-PARTS-MANUAL-BOSS-FE-/130666904992?_trksid=p4340.m185&_trkparms=algo%3DSIC.NPJS%26its%3DI%26itu%3DUA%26otn%3D5%26pmod%3D360318735323%26ps%3D63%26clkid%3D7227766569948979360

BT

 

[goodnigh]

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

 

[Wolverine]

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?

 

[goodnigh]

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

 

[Wolverine]

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/techarticles/mump_1001_boss_351_block_buildup/viewall.html#ixzz1q19bBDkc

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.

 

[cobra3073]

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

 

[Wolverine]

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

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...

 

[droptop73]

That would mean .038" valve clearance... That is a ton of lash!

 

[Wolverine]

That would mean .038" valve clearance... That is a ton of lash!

That is what I thought, unless there is a LASH FACTOR where a lash of .022 actually leaves a clearance of .038"....

My head hurts...

My intention was to use the 351 Boss as a basis for selecting my CAM. As it turns out, based on all the numbers I have seen, I am in the ballpark more or less.

I just don't understand why no one has a published page out of a book? Although the best information seems to be the cam part# supplied in this post, and use of the 302HO/Boss camshaft specification.

 

[droptop73]

Why not go with a more modern profile? I'm planning to use a hydraulic roller cam in the new shortblock I am planning. If the cam is ground with a reduced base circle standard Ford roller lifters and dog bones can be used with a 351W valley spider.

 

[Wolverine]

Why not go with a more modern profile? I'm planning to use a hydraulic roller cam in the new shortblock I am planning. If the cam is ground with a reduced base circle standard Ford roller lifters and dog bones can be used with a 351W valley spider.

Not sure what modern profile means....or dog bones...or valley spider...I am familiar with Ford roller lifters...in that regard I am sticking with my tried and true Harland Sharps.

As I understand it, the 351 Boss rolled pretty good out of the box. I don't mind improving on that a little bit, but this would be my daily driver so I am not interested in bouncing around like I was sitting on a Harley ...though I don't mind a little shake, rattle and roll.

 

[c9zx]

This is Crane's version of the D1ZZ-6250-B. http://www.cranecams.com/product/cart.php?m=product_detail&p=24493

It is not exactly the same as the original. I would use a more recent profile with somewhat faster ramps, and use split duration and lift favoring the exhaust. The Exh flow/Int flow ratios are a bit low on the 4V heads. Also consider a relatively wide LSA of 112 to 114 for a daily driver.

This is something that would meet your needs. http://schneidercams.com/256-64F_351Csolid.aspx

Chuck

 

[Wolverine]

This is Crane's version of the D1ZZ-6250-B. http://www.cranecams.com/product/cart.php?m=product_detail&p=24493

It is not exactly the same as the original. I would use a more recent profile with somewhat faster ramps, and use split duration and lift favoring the exhaust. The Exh flow/Int flow ratios are a bit low on the 4V heads. Also consider a relatively wide LSA of 112 to 114 for a daily driver.

This is something that would meet your needs. http://schneidercams.com/256-64F_351Csolid.aspx

Chuck

Thanks for doing the research. I will seriously consider it. FYI, this is a comparison of the cam I have now, with what you recommended. I can see where your recommendation may be more suited for my application.

Schneider Isky

Lifter Type Solid Hydraulic

Part Number: none 431264

Grind Number: 256-64F 431264

Intake Duration (gross): 256 264

Exhaust Duration (gross): 264 264

Intake Duration (.050”): 212 214

Exhaust Duration (.050”): 224 214

Intake Valve Lift*: .502 .525

Exhaust Valve Lift*: .519 .525

Lobe Separation: 112 108

Intake Valve Lash: .012"

Exhaust Valve Lash: .014"

RPM Range: 1500-5500 2000-5800

 

[c9zx]

It was just one cam I found quickly (5 minutes). Please spend the time doing detailed searches before making a decision. There is a limited selection of off the shelf solid flat tappet cams that are right for a daily driver. Most are too aggressive for the intended use you described. In general the 351C 4V like short durations, high lifts, and 112-114 LSA for daily use. Chuck

 

[droptop73]

Why not go with a more modern profile? I'm planning to use a hydraulic roller cam in the new shortblock I am planning. If the cam is ground with a reduced base circle standard Ford roller lifters and dog bones can be used with a 351W valley spider.

Not sure what modern profile means....or dog bones...or valley spider...I am familiar with Ford roller lifters...in that regard I am sticking with my tried and true Harland Sharps.

As I understand it, the 351 Boss rolled pretty good out of the box. I don't mind improving on that a little bit, but this would be my daily driver so I am not interested in bouncing around like I was sitting on a Harley ...though I don't mind a little shake, rattle and roll.

By modern profiles I mean cam lobe shape. Lobe technology has radically changed since the 70's. Opening and closing rates are much greater with modern (especially roller) cam grinds. They require less spring pressure and are easier on valvetrain parts. The dog bones are the pieces that keep roller lifters aligned and the roller headed the right direction on the cam and the spider is a stamped piece of sheet steel that holds the dog bones to keep them in place on the lifters, both are stock Ford parts and reasonably priced.

 

[Wolverine]

And, for the record, anything I put in my car that doesn't work out is MY FAULT. I understand suggestions are just suggestions. Never hurts to take a look see at a different perspective.

 

[Widowmaker00]

And, for the record, anything I put in my car that doesn't work out is MY FAULT. I understand suggestions are just suggestions. Never hurts to take a look see at a different perspective.

Just thought I'd throw out there my cam..

http://www.jegs.com/i/Comp-Cams/249/32-221-3/10002/-1?parentProductId=

Just lopes a tiny bit and seemed to help out power throughout the entire rpm range.