I am preparing to build a 390 for my '69 Ranger. This is going to be real mild with only a 4bbl carb and dual exhaust. Stock compression, stock heads, stock cast iron intake. I am trying to decide between the Crane 260 and 266. Does anybody know what the factory cam specs were? Trying to do a comparison here to see how far the 260 and 266 are from stock. Thanks for any help.

 

Not sure if it changed, but the only spec in the 1972 book is .427 is the theoretical valve lift. (No other timing or duration spec)

Crane does offer a "Blueprint" cam for a 390 though:

Application Series & Grind Number
Replacement for factory 275 HP, 390 cu. in. camshaft.
Basic RPM 1000-3500
BluePrinted C7AZ-6250-A

Cam Specifications
Degrees Duration @ .050 Int./Exh. = 192/199
Degree Lobe Separation = 112
Open/Close @.050" Cam Lift Int./Exh. (17) 29 30.5 (11.5)
Gross Lift Int./Exh. .435 .438

See it here:


BluePrint

 

’68 – ’76 360, 390 Truck

Valve Lift
Intake .427”
Exhaust .431”

Duration @ .006”
Intake 256*
Exhaust 266*

Timing @ .006”
Intake Opens 13* BTDC
Intake Closes 63* ATDC
Exhaust Opens 63* BBDC
Exhaust Closes 23* ATDC

Overlap 36*

 

OK, thanks, I knew I could get the answer here. The 260 seems to be the way to go, it offers just a little more duration than the stocker but a LOT more lift. Just the ticket for off-the-line pull. I think this cam is pretty popular around here - how are you guys setting them up? Straight up? Can I use stock springs with that much lift (.501/.533)? Or should I use a 266 and just advance it 2 degrees or so?

 

I would either run the 260 (343901) or 272 (343941) due to the dual pattern design.

I have run a cam similar to the 343941 in a 351 and it was very difficult to tell it was even in there (except it was a strong runner)

I would also run Cranes valve spring and retainer kit, it is cheap, and 30 plus year old valve springs are a bit of a crap shoot.....

Just my $.02