Moparts Tech Archive
Main studs or bolts?340SIX
From: NEW ORLEANS,LA.
Registered: Jun 2000
posted 07-04-2002 07:19 PM
should i use main studs or bolts for the 422ci small block? it is a mild build 10.75-11.0 compression elde heads solid cam 560/575 lift 245/252@ 0.050 steel crank,h
Main studs, definitely! Don't skimp on critical fasteners, go with ARP
imho studs are always better than bolts (provided you can use them) for a number of reasons. better clamping,negligible wear and tear on the cast threads. the drawbacks would be head removal (in car) and the common practice of align honing the mains when studs are used. the engine you've listed is not a low buck build so imho it should be honed anyway.
forgot to mention that in some cases the thrust maincap may need the bolt holes enlargend so you can get the thrust faces to line up.
Studs are stronger for several reasons:
Bolts can more than get the job done but studs can get the job done better!
You will more than likely have to align hone when switching to studs, more times than not the studs will stress everything differently and the bores won't be round anymore with the studs. Sometimes you can get away without it, you need a good dial bore gauge to tell either way.
Drawbacks? Well, in a SB they hit the oil pump alot of times, and you have to grind the pump/shorten the stud or nut to make it fit. So that might take a little while to sort out.
I definitely wouldn't use them in a retrofit kind of deal (you know, take the mains off a running motor and put studs in--that is probably not a good idea), but when building a new/freshly machined/fully machined motor I can't think of any reason not to use them. Always supply your machinist with the studs when it is time for the align hone so he can use them at the prescribed torque during the machining process.
Later on you might get greedy for more power & if the bottom end is bullet proof it's one less thing to worry about.
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