NSA vs. SA rocker arms

[Craig 94 TA GT]

I did a search on this topic but I can't find a definite answer for my specific needs. My question is...I'm planning on replacing the rocker arms/springs, and fixing my intake leak. Firstly, I want to keep the stock cam and lifters...and in the future, I MIGHT go as high as the Hotcam, but that's it. So I'd say I'll never go higher than 6000 RPM now, 6200 in the future. Which would be recommended for this, NSA or SA roller rocker arms? (I'm mainly looking at the Comp Cam 1.6 Pro Mags - either 3/8" or 7/16"). I know the NSA is only a few dollars more with the guideplates, but is the extra strength really worth it? How would I go about installing the guideplates? Also, since the T/A already came with hardened pushrods in '94, would I need to replace them if I go with NSA rocker arms (106k miles)? Lastly, would LT4 valve springs be sufficient for this project?

Sorry so many questions...the motor seems to be getting worse in terms of MPG and performance, so I want to make sure I get this done right. I would greatly appreciate any help and advice...thanks in advance.

[Fastbird93]

I used to be an advocate of SA rockers, until I had them a little too loose on a VERY agressive cam. They jumped off the valve stem, and six got the alignment tabs chewed up and chromemoly bits all in my new motor. That said....

Go NSA. It's a much more stable setup, and you won't have to worry about any little alignment tabs being chewed off. Heed this though:

The ONLY guideplates made with the proper offset for an LT1 are the GMPP part number 14011051. They're advertised for a V6 but are fine with the LT1. Injuneer can back this up. The LT1 has a .050" greater offset than the standard SBC. Combination Motorsports makes a guideplate specifically for the LT1, but in THIS PICTURE you can see otherwise. Props to shoebox for the great comparison pic.

The guideplates themselves are very easy to install. They simple get sandwiched between the head and the rocker stud. That said, may as well convert to 7/16 studs and rockers since you're removing the studs anyway.

When I was putting everything in my car, I couldn't believe how much more stable everything seemed. I have absolutely no fear for my valvetrain at this point.

[Craig 94 TA GT]

Fastbird, thanks for the reply. Although I'm never going to have a cam as hot as yours, I think you've convinced me to go for the NSA setup now. So I guess I'll get the whole package...NSA 1.6 Pro Magnums that accomodate 7/16" studs, the 7/16" studs themselves, and GM guideplates (the ones for the 6 cylinder). Would you know if our hardened pushrods are good enough to hold up in this setup, or should I just replace them since they are cheap and I have 106k miles. Also, what springs did you use? I'm planning on the LT4 ones. Lastly, would you know if K-Line 11/32 valve stem seals are a direct replacement for stock LT1 valves? Thanks a bunch...

[Craig 94 TA GT]

I forgot to ask one more thing...are the 7/16" rocker studs a direct bolt-on replacement with no machining? Forgive me, I've never seen our LT1 head before. Thanks.

[Fastbird93]

Fastbird, thanks for the reply. Although I'm never going to have a cam as hot as yours, I think you've convinced me to go for the NSA setup now. So I guess I'll get the whole package...NSA 1.6 Pro Magnums that accomodate 7/16" studs, the 7/16" studs themselves, and GM guideplates (the ones for the 6 cylinder). Would you know if our hardened pushrods are good enough to hold up in this setup, or should I just replace them since they are cheap and I have 106k miles. Also, what springs did you use? I'm planning on the LT4 ones. Lastly, would you know if K-Line 11/32 valve stem seals are a direct replacement for stock LT1 valves? Thanks a bunch...

If you've got the factory hardened pushrods you should be ok. If you feel like buying new ones it won't hurt anything.

I used the EX Components (CM's in-house stuff) 618 springs. Dual coil, 150# of seat pressure installed at 1.8", 350# open pressure @ .600 lift. But I'm running a one off Joe Overton cam too!!!! LT4 springs should do you fine.

I honestly don't knoww about the valve stem seals.

I forgot to ask one more thing...are the 7/16" rocker studs a direct bolt-on replacement with no machining? Forgive me, I've never seen our LT1 head before. Thanks.

Yes they are. The factory 3/8 studs actually are 7/16 on the bottom part that screws into the head.

[Craig 94 TA GT]

Thanks again for the info Fastbird...I will get the NSA valvetrain setup now...just a matter of a few days

[fastTa]

I would definitely vote to use the NSA's. The 94's did indeed come with a "type" of hardened push rod, but they are not as "hard" as an aftermarket hardened pushrods.

But even that being said, I still wouldn't even use an aftermarket hardened push rod with a guideplate. If you call any f-body speed shop they will tell you to use a chrome-moly push rod with a guideplate and there is good reason for this. When you are putting together your valvetrain, that is one of the most critical systems on your motor. Their is a lot of friction and some play between the pushrod and guidplate and chrome-moly pushrods are much more up to the challenege for use with a guidplate. They cost a little more but when you are talking about your valve train, it is money very well spent.

I can attest to Combination Motorsports' first version of their guideplates not being up to par, but they have corrected the minor problem since then.

But I would still use the "Bowtie" (GMPP) guideplates, they are a good design.

[Craig 94 TA GT]

Thanks for the reply Kevin...I guess I will get the chromemoly ones then. Are these the correct ones?
Part number: CCA-7940-16
Description: Comp Cams Hi-Tech 5-16" Chromemoly Pushrods 1993-97 350 LT1 - 16 pkg.
Price: $114.50

Also, how much more work would be involved if I removed the heads and changed the head gaskets (since I'm removing the intake manifold to fix the leak, and removing the valve covers already)? And would you have a ballpark figure for the cost of a valve job and/or light port and polish on our LT1 heads? Thanks in advance...

[fastTa]

Thanks for the reply Kevin...I guess I will get the chromemoly ones then. Are these the correct ones?
Part number: CCA-7940-16
Description: Comp Cams Hi-Tech 5-16" Chromemoly Pushrods 1993-97 350 LT1 - 16 pkg.
Price: $114.50

Also, how much more work would be involved if I removed the heads and changed the head gaskets (since I'm removing the intake manifold to fix the leak, and removing the valve covers already)? And would you have a ballpark figure for the cost of a valve job and/or light port and polish on our LT1 heads? Thanks in advance...

That is the right pushrod as long as you don't mill your heads. You would need the 7939's if you get your heads milled. Removing the heads is more work, but as long as you keep track of where all the bolts and parts go, you will be fine.

$400-$1000 for the heads depending on what type of valves, retainers, locks, how large of a valve, and the extent and type of porting.

If you used something like a Ferrea or Manley valve, 2.00" intake and 1.56" exhaust (1.60" exhaust will be more expensive as it involves more machine work), re-used your existing retainers and locks, and had a mild port match, and a combustion chamber clean up, it would be roughly $500.

[Craig 94 TA GT]

OK, I don't think I will do any head work at this time then...a little over the project's budget. However, I wonder if it would really be worth it just to replace the head gaskets since the manifold, alternator, etc. are already off. I am also buying the LT4 springs, caps, keys and shims which will hopefully be OK.

By the way, would you stick with GM gaskets (valve covers, intake manifold, heads), or do you think Fel Pro would be OK? Thanks again in advance.

[fastTa]

OK, I don't think I will do any head work at this time then...a little over the project's budget. However, I wonder if it would really be worth it just to replace the head gaskets since the manifold, alternator, etc. are already off. I am also buying the LT4 springs, caps, keys and shims which will hopefully be OK.

By the way, would you stick with GM gaskets (valve covers, intake manifold, heads), or do you think Fel Pro would be OK? Thanks again in advance.

Craig, if I remeber correctly, I think your car had a few miles. If it were me, I would probably go ahead and change the head gaskets.

Lots of guys use the Impala head gaskets as a replacement. Stock LT1 head gaskets are .050" thickness. The impy gaskets are designed for use with an iron head and they are thinner. I think .030" if i remeber correctly. This would give you about a .3 increase in compression and a few ponies as well. If your motor uses oil right now, you could go with the Fel-Pro 1074's. They are .039" thickness. And since your there, have you ever replaced the timing hain?

Here is a super deal on a valvetrain package BTW:

http://www.lt1f-body.racenet.net/valvetrain.php

Happy wrenchin!

[Craig 94 TA GT]

Thanks Kevin...it looks like I had to add a bit extra for the head removal. I have absolutely no oil loss/burning (besides the intake oil leak) and 106k on the clock. But as far as head gaskets, I don't think I want to go too thin like the Impala's, so the Felpro's will probably be just fine. So now the list looks like...
Comp Cams 1.6 NSA Rocker Arms
Comp Cams chromemoly pushrods
Comp Cams rocker arm studs
GM guideplates (x 8)
LT4 valve springs
LT4 valve caps kit
LT4 valve keys kit
LT4 valve springs shims
GM Intake valve seals (x 16)
GM Exhaust valve seals (x 16)
Felpro Intake manifold gasket kit
Felpro Valve cover gasket kit
Screw-in valve cover breather for LT1
Felpro Exhaust manifold gasket set
Felpro .039 Head gaskets (x 2)
GM timing chain

How the heck did the project of fixing the intake manifold leak turn into this? lol This will probably run me about $750, which isn't tooo bad...but it's a lot more than I was preparing for when I was only going to fix the leak.

Thanks again for all your help.

[fastTa]

....How the heck did the project of fixing the intake manifold leak turn into this? lol This will probably run me about $750, which isn't tooo bad...but it's a lot more than I was preparing for when I was only going to fix the leak.

Thanks again for all your help.

It's an infectious disease spread rapidly through contact of an f-body. It will only get worse. You will start craving more and more power. You won't be able to exhibit any self control.......................oh wait............that's me................never mind.













Anytime Craig.

[fastTa]

Hey Craig I forgot to tell you. Here is a very inexpensive place to get FelPro gaskets.

[Kevin - Blown 95 TA]

Hey Craig I forgot to tell you. Here is a very inexpensive place to get FelPro gaskets.

Where might that be Kev?