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I know drag racers who run very high rpm with two bolt mains, but road racing puts a lot more strain on a motor than drag racing. It takes a lot of abuse to make the two bolt caps walk in their registers when they are tightened properly, but I like to build-in a margin of safety (some people call that over-building). A naturally aspirated motor rev-limited at 6000 rpm doesn't need the girdle. If the rev-limit is 7000 rpm or higher, and you planned to run in the higher rpm range full time (not just a blast on a freeway on-ramp), then I would install the girdle.

The part of the girdle that bends around the oil pump will interfere with the oil pan. What I've done in the past is remove that part of the girdle with a hack saw. The alternative is to bang the pan out with a ball peen hammer and hope nobody looks under your car. Smiler

-G
When I was building my 460 I was looking for a high nodularity 429 4 bolt main block. After I found the motor I wanted I was told I could hve used a 'thick web' block and a girdle. These guys get 1000HP out of normally aspirated 460s

So I guess, if you have a strong block go for the insurance and use the girdle.

Denis
quote:
Originally posted by larryw:
George, should the girdle be torqued in place before crankshaft bearing alignment is checked and/or corrected?


My preference would be to align-hone it with the girdle in place.

quote:
Originally posted by LF - TP 2511:
... unless you somehow plan to run road races in the 6000+ rpm range, I don't think he would advise a girdle, either ... George?


I'd rather provide guidelines and let people form their own opinions. It won't hurt anything to install the girdle, even if its not needed. Larry's point about deciding to run the motor harder in the future is a valid one. Girdles are very common with small block Chevys and Windsors, and although the Cleveland lower end is much beefier, Ford engineers specified 4 bolt mains for the 351 Cobra Jet and Boss 351 for a reason, not to waste Ford's money.

-G
Last edited by George P
Larry W....that windage tray is a nice find. I have the Armando pan and have been looking at windage trays. That one bolts to the pan rails and not the main caps like the Milodon version and others, which I like better. I would rather just leave the main caps alone.

I wonder how many issues you run into with making the gasket seal...it looks like there are gaps in the metal instead of one continuous piece running along the pan rail. How would you seal that? I know you have to use two sets of gaskets and probably a lot of gasket sealer?
quote:
Originally posted by DOES 200:
Is that similar to what I have sticking through my valve covers? Other owner told me would do 6,500 RPM all day.....


There are two types of 351-C 'girdles': one is a massive metal plate inside the oil pan that reinforces the crankshaft's main bearing caps while the other is a set of bars that clamp all the rocker studs together under the rocker covers, reinforcing them. Your special SVO covers are much thicker than normal, with special long rocker studs extended thru the thick cover top. The effect is the same as a girdle inside, but they weren't popular with go-fasters 'cause it's much less convenient to get inside the covers & adjust valve lash with 8 bolts plus 8 stud-nuts to r & r each time- on each head. If you ever find any, pick up as many of the spare stud-seals as you can find- each top acorn nut has (or had) a conical washer and a dead-soft copper seal under it to prevent oil leaks. They've all been unavailable from Ford/SVO for decades.
Jack,

I can't see how spinning those acorn nuts off, then the eight rocker cover screws, popping off the rocker cover and having your rockers staring back at you ready to adjust is any less convenient than removing the rocker cover and then removing the fasteners required to split a two piece girdle in half that clamps a bunch of special adjuster nuts. Am I missing something? Perhaps those SVO covers are just rare, not a weak design?
Last edited by larryw
George,

Is "cap walk" in a two bolt main engine at stressful RPMs a side to side or a fore and aft sliding movement?

Could it be restrained by, say, short hardened .250" dia. dowels fitted into holes drilled into the cap and block in lieu of four bolt caps? They could be positioned where the outer bolts of a four bolt cap would usually go and, being much smaller than a 3/8" bolt, would not compromise the two bolt caps(?).

An align bore would probably be a good idea afterward.

Or is it actually the cap lifting away from the block due the elasticity of the two bolts (or studs) stretching and recovering that the two outboard bolts of a four bolt cap reinforce?
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