LT1 and LT4 Rocker arm studs, question
08-23-2011, 07:59 PM
#1
Race Director
Thread Starter
LT1 and LT4 Rocker arm studs, question
The stud hole on my LT4 heads are 7/16-14 threads. Now comes the question: When buying the GM hot cam kit with roller rockers, what thread will the top of the stud be? 3/8" or 7/16" ? I think the OEM LT4 has 7/16" thread on the top of the rocker stud. Am I right or wrong?
I need to buy rocker studs and need to know what to buy. Thanks guys.
I need to buy rocker studs and need to know what to buy. Thanks guys.
08-23-2011, 08:14 PM
#2
Le Mans Master
OEM LT4 has 7/16 on bottom and 10mm on top. The OEM rockers are non-adjustable. The Hot Cam kit has 3/8 adjustable rockers in it. So you need 3/8 upper with 7/16 bottom.
Yep, what he said.
08-23-2011, 09:00 PM
#4
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IIRC, when I installed the HOT cam in my LT4 I used the same rockers/studs. No adjustment needed. I did, however, go to adjustable studs when getting the heads ported and going to trick flow push rods and pro comp rockers. I am unfamiliar with the particulars of the 'kit'.
Actually, I still have the studs and rockers that came with the original LT4. They have 127K miles on them but you are welcome to them if you can use them. Perhaps you only need the HOT cam?
Actually, I still have the studs and rockers that came with the original LT4. They have 127K miles on them but you are welcome to them if you can use them. Perhaps you only need the HOT cam?
Last edited by SouthernSon; 08-23-2011 at 09:02 PM.
08-23-2011, 09:44 PM
#5
Tech Contributor
Since you need to buy both rockers and studs, buy what you want....3/8" or 7/16" on the top. All are 7/16" on the bottom.
The nice thing with the 3/8" studs is that you can use self-aligning rocker arms and traditional pushrods. This eliminates the need for guide plates and hardened pushrods.
If you go the 7/16" route, you will need both guide plates and hardened pushrods. This negates the cost savings of non self-aligning arms vs the self-aligning.
If you plan to regularly beat on the engine and add additional power in the future, I would go 7/16". For a basic mild street engine, 3/8" studs are more than sufficient.
The nice thing with the 3/8" studs is that you can use self-aligning rocker arms and traditional pushrods. This eliminates the need for guide plates and hardened pushrods.
If you go the 7/16" route, you will need both guide plates and hardened pushrods. This negates the cost savings of non self-aligning arms vs the self-aligning.
If you plan to regularly beat on the engine and add additional power in the future, I would go 7/16". For a basic mild street engine, 3/8" studs are more than sufficient.
08-23-2011, 10:48 PM
#6
Melting Slicks
The LT4 "hot cam" is a drop in direct replacement nothing else needed upgrade for an LT4.
On my LT4, I reused my rockers, studs, lifters, pushrods, the whole enchilada. Only replaced my LT4 valve springs with new LT4 valve springs, installed new valve seals and upgraded my timing chain to an LT4 "extreme duty" chain .
If you don't have an LT4 (too bad) then things do get more complicated.
On my LT4, I reused my rockers, studs, lifters, pushrods, the whole enchilada. Only replaced my LT4 valve springs with new LT4 valve springs, installed new valve seals and upgraded my timing chain to an LT4 "extreme duty" chain .
If you don't have an LT4 (too bad) then things do get more complicated.
08-24-2011, 07:48 PM
#7
Race Director
Thread Starter
After carefully reading what is in the GM Hot Cam Kit, I found that it includes the rocker arms for a LT1 motor(heads) as the kit is labelled Hot cam kit for LT1s. I could buy LT4 rocker arms and studs from a GM stealership as my heads are true OEM LT4 heads, but the studs from them are 8.99 each! 
I currently have Crane's self alligning roller rockers(1.5 ratio) on my LT1 and they work just fine. As suggested I'll just go with the full hot cam kit and use the supplied parts. Adjusting valves is easy for me. I'm doing a top end swap on my 92 LT1 to the LT4.
I currently have Crane's self alligning roller rockers(1.5 ratio) on my LT1 and they work just fine. As suggested I'll just go with the full hot cam kit and use the supplied parts. Adjusting valves is easy for me. I'm doing a top end swap on my 92 LT1 to the LT4.
08-25-2011, 04:55 PM
#8
Race Director
Thread Starter
IIRC, when I installed the HOT cam in my LT4 I used the same rockers/studs. No adjustment needed. I did, however, go to adjustable studs when getting the heads ported and going to trick flow push rods and pro comp rockers. I am unfamiliar with the particulars of the 'kit'.
Actually, I still have the studs and rockers that came with the original LT4. They have 127K miles on them but you are welcome to them if you can use them. Perhaps you only need the HOT cam?
Actually, I still have the studs and rockers that came with the original LT4. They have 127K miles on them but you are welcome to them if you can use them. Perhaps you only need the HOT cam?
08-25-2011, 05:45 PM
#9
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I don't have the pictures at my present location but perhaps I can get a picture or two to you next week. I also have the 28# injectors that I replaced with 32#'s last Dec. They, too, have 127K miles but were working perfectly. Email me if you like and I'll see what all I may have that might be of use to you.
08-25-2011, 08:54 PM
#10
Race Director
Thread Starter
I don't have the pictures at my present location but perhaps I can get a picture or two to you next week. I also have the 28# injectors that I replaced with 32#'s last Dec. They, too, have 127K miles but were working perfectly. Email me if you like and I'll see what all I may have that might be of use to you.
08-25-2011, 10:58 PM
#11
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Atlanta Center 84-88, went into FSS in Mississippi 88-96, Nashville FSS 96-2005, and, finally, Lockheed Martin FSS 2005-2010 (please don't blame me for LM's total screw up of FSS, we old heads did all we could in spite of LM).
08-26-2011, 12:30 PM
#12
Tech Contributor
08-26-2011, 06:07 PM
#13
Race Director
Thread Starter
You only need guide plates if you use non self-aligning rocker arms. I ran the HOT Cam for many years on my LT4, swapping out the OEM rocker arms and studs for 3/8" studs and self-aligning rockers in order to gain adjustability. This is what's in the HOT Cam kit, and as such you do not need guide plates.
08-26-2011, 06:12 PM
#14
Race Director
Thread Starter
We probably talked with each other back then. Again thanks for the offer, but Sat I'm heading to the auto Fair at CLT motor speedway where there are many vendors selling the Hot Cam Kit, I hope.
08-26-2011, 08:58 PM
#15
Tech Contributor
When I did the HOT Cam swap, the car was pretty mild from an exhaust standpoint and lots of people talked about rocker arm clatter when remaining with the OEM non-adjustable rockers. With that in mind, I figured for an extra couple hundred dollars..."Why not?". 
08-27-2011, 08:55 AM
#16
Race Director
Thread Starter
I found that I can use my LT1 magnesium valve covers on the LT4 heads. They fit just fine.
08-27-2011, 07:12 PM
#17
Le Mans Master
Rocker arm chatter? Hummmm......never hear of that problem on a LT4. Maybe that's why the LT4 has a different knock sensor. My Crane self aligning gold rockers on my LT1 are just as quiet as the stamped arms.
I found that I can use my LT1 magnesium valve covers on the LT4 heads. They fit just fine.
I found that I can use my LT1 magnesium valve covers on the LT4 heads. They fit just fine.
08-28-2011, 01:48 PM
#19
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08-28-2011, 02:48 PM
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