I need some help guys. I bought a 383 LT1 which has ARP Rocker arm studs (Part# 134-7101) which has a 3/8 shank dia. It also came with Harland Sharp 1.6 Ratio rocker arms for 3/8" stud. The overall stud height is 1.750" based on ARP's catalog. This engine also came with rocker arm stud girdles from performance products.

Can I use these stud girdles with this rocker arm stud? After looking at ARP's catalog they show rocker arm studs for use with stud girdles with shaft lengths of 1.900-2.100" and rocker arm shank dia. that are 7/16" instead of 3/8"

ARP is closed so I cannot call them. Can someone please help me out here? Will I need new/taller rocker arm studs to get these stud girdles to work? I cannot get a 7/16" shank dia. stud because the rocker arms are for a 3/8" stud and I do not want to buy new ones if I do not have to.

My rods have 7.350 and .080 etched into them, not sure if this is necessary to know to help with the stud height.

Also, if all this becomes a real issue, do I really need the stud girdles? The engine is expected to put out ~450 hp.

 

The stud girdle should come with it's own rocker nuts. They'll hold down the rocker arm just like the normal poly lock nuts but will have an extended end for the girdle to bolt around. The longer rocker studs allows for taller valve springs which also need longer valves and longer pushrods to correct the valve train geometry. Whenever you're mix and matching parts, valve train geometry always needs to be checked. Pushrod length can be just about anything depending on your combination of parts.

If the girdle nuts are for 7/16" studs then you can't use them without 7/16 studs which will also need 7/16" SBC rockers.

I doubt you have spring pressures anywhere near where you need a girdle. Sell it on Ebay. If your valve springs have 200-300 pounds of seat pressure, I'd recommend a girdle. You probably have 300 pounds of open pressure.

I run a girdle on my BBC. The valve springs also have 800 pounds of open pressure and I spin the engine to 7400 rpm.

 

I do not have the stud girdle nuts so I cannot tell from that. I will see what I can find about the spring pressures.

Be back shortly...

Thanks

 

Ok, so my springs are the comp cams beehive springs PN# 26918-16 which has open spring rate of 318 lbs and installed at 130 lbs.

I think I will not use the stud girdles and not deal with having to change some of these parts out.

On the box the valve springs came in it says these springs are High performance GM LS1 valve springs... now is this a problem since I have an LT1?