Preferred 351W Block??

[auto10x]

I have heard / seen several reasons why one 351W block may be more desireable than another:
To qualify for emmission exemption (older is better)
Thicker webs ('74 and earlier)
Slightly lower / higher deck heights ('69 & '70 / '71 on up)
Are there other reasons? Other than for emission qualifications, are there really significant reasons to go with one rather than another? If so, which is the most desireable.
Thanks,
auto10x
Bill

[Rufus]

I'm at work and don't have access to my Ford reference materials and can't remember. But if there are different crank bearing journal diameters, the small dia would be prefferable from the standpoint of putting less heat into the oil for track use...

Maybe someone else can clarify.

[PSB]

If you're staying under 600hp, and you're not planning on spinning it above ~6500 rpm, any year block will do. The only differnence you didn't already mention is '94-'97 blocks are set up for roller lifters. Crank journal diameters are the same on all years.

If you're building a 750hp supercharged monster motor or a high RPM motor, the best way to go is a Sportsman block.


Pete

[Rufus]

BTW - My Ford SVO catalog shows the SVO 351 blocks have 2.749" dia main bearing journals compared to 3.0 for the "street" blocks. Although unstated Pete's answer probably only referring to the street blocks.

Bob

[auto10x]

Thanks for your time and information.
auto10x
Bill

[PSB]

Originally posted by Rufus


BTW - My Ford SVO catalog shows the SVO 351 blocks have 2.749" dia main bearing journals compared to 3.0 for the "street" blocks. Although unstated Pete's answer probably only referring to the street blocks.

Bob

The Sportsman/SVO/FRPP (or whatever they're calling it this week) block (Part # M-6010-N351 to be specific) does have smaller mains - that's why I said it'd be the way to go if your wanting a high RPM motor. Here's the description of that block from the FRPP web page:

Cast Iron block material
*9.500" nominal deck height
*434 CID capacity
*Non-Siamese cylinder design
*4.000-4.030" cylinder bore range
*Wet oil sump design
*2.7490" crankshaft journal diameter
*Four on 2,3,4 main cap bolts
*Nodular iron bearing cap material
*4.250" recommended max. stroke
*750 recommended max. HP @ 8600 RPM
*One piece rear crankshaft seal type
*Std cam bearing design
*Block oil filter mount
*Can be bored/stroked to produce 434 cu. in.
*Weighs approximately 205 lbs
*Circle track and drag racing
*Semi-finished lifter bores and main bearing bores must be honed to fit
351 Ford Street/Strip, 9.500 deck ht


Pete

[Mr.Fixit]

Year of car title is aconcern, pre-73 if it matters for you. If you are building a max-displacement stroker., than a post 71 has more deck height.