F351C head identication
 

I am somewhat doubtful if I have a Boss head as told. Is there anyway that one can visually see if my heads are Boss without removing valve covers etc. I know it is a 4V and that it is a 4 bolt main bearing. I am dubious if this is a Boss set-up and help appreciated. I was told the block was originally a longblock- does this effect whether it could have been originally a Boss block (and crank- high nodular iron) and heads? thanks, Ed

351c boss ID is D1ZE-B(4v with quench heads (61-64cc).There is no 351c boss block per se but casting number will be D1ZE-B(4 bolt main)any 4 bolt main block is the same as far as strength and iron quaility goes. chuck

> I am somewhat doubtful if I have a Boss head as told. Is there anyway that
> one can visually see if my heads are Boss without removing valve covers etc.

No, you can't even be certain then. Standard 4V heads can be converted
to adjustable valve train which is the primary difference (relative to
closed chamber heads). Be aware there were H.O. heads that are similar
to Boss heads but have open chambers. One test can tell if it's not
a Boss or HO. If you look down at top of keepers they should not butt
together. If they do, then it has the multi-groove, loose-fit, keepers
of the standard 351C. The only way to be sure is to check the casting
numbers. Casting codes (e.g. DOAE, ARD1AE, etc.) are located on the
underside of one of the middle intake ports and foundry marks (CC or CF
for U.S. heads) are located in the rocker arm area.

> I know it is a 4V and that it is a 4 bolt main bearing. I am dubious if
> this is a Boss set-up and help appreciated. I was told the block was
> originally a longblock- does this effect whether it could have been
> originally a Boss block (and crank- high nodular iron) and heads?

The Boss 351 and HO blocks were standard 4 bolt main 351C blocks that
were Brinell tested for hardness. Heads were 4V closed chamber with
single groove valves and adjustable valve train (studs, guideplates,
adjustable rockers) to suit the solid lifter cam. Finned flat top
cast aluminum valve covers. Like the block, the crank was a production
iron piece (not steel like some claim) but was tested for nodularity
(otherwise same as any other 351C crank). Pistons were forged with a
dome. Rods were 351C parts with better rod bolts. Carb was a 4300D
Motorcraft sprad bore on a matching aluminum dual plane intake. The
distributor was a dual point with vacuum advance.

If your engine is indeed a real Boss, be aware it should have a heavier
harmonic balancer. The Boss balancer is thicker/heavier than 4V/CJ
part which is heavier than 2V part. Also the reciprocating assembly
was balanced to something other than the standard 28.2 oz-in. It was
27.something but I don't recall exactly. This is important to know
if swapping out the balancer or flywheel.

Dan Jones