350 groundpounder

iTrader: (5)

Alright im getting some of this build figured out. As previosly posted i am using the cast cc305 cam with cc850 lifters.
I decided on the GM 1.6 roller rockers from the hotcam kit. They are 3/8 size.
Im going to use the ARP 3/8 rocker studs for extra strength.
Once put together im going to measure for the correct pushrod length and go with trick flow chromemoly pushrods.
Question #1, Should i use the stock pushrod thickness since im sticking with 3/8 rr's or go with the thicker walled pushrods?
Question #2, After reading about lots of cam and lifter failures because of possible too much seat/open pressures i have decided to play it safe and use maybe 130 on the seat and 350 tops open pressure springs. Most double springs exceed these pressures unfortunately. Would the pac 1218's be a good spring for this set up? I want to stay clear of comp springs. Any other good spring suggestions?
It seems like a delicate balance between not enough spring pressure and less stress on the valvetrain or too much spring pressure to keep away valve float at higher rpms. Im simply just not going to rev over 6000-6200 when racing and prob not over 5500rpm with 95% of my street driving. So i should get away with lower spring pressures?

ACE1252

I'm running PAC1518's with no trouble(CC503). It's the same as the 1218's but are nitrided(I think) and may be able to have a little more lift. I think they have 130 on the seat closed like the 1218's.

I'm running 7/16 NSA Pro Mags. Since they are NSA, I have to use guideplates(trickflow) and went with stock length Comp Cams hardened pushrods. I'm not sure what the wall thickness is, but I don't think you'd have any trouble with the stock thickness.

However, best to wait on some other opinions.

Tomhames

iTrader: (3)

Those pac1518's are very nice springs.(1218's are decent as well) .

I put them in after I had the comps 918's FAIL..... I didn't even know I had the comps in my engine until I had 4 (maybe 3) broken at one time. WTF. And the comps weren't from the "bad" batch 10 or so years ago. Beware.

350 groundpounder

iTrader: (5)

Thanks guys. What retainers, locks did you use with the pac springs? Install height for 130lbs on the seat? I dont want to do any machining on the heads to get the springs to fit. Hopefully they just fit right in.

ACE1252

I used this hardware with my 1518s. I didn't need any machine work on my heads for how I set them up.

Comp Cams Spring Locator Kit CCA-4705-16
Comp Cams Spring Retainers 10* CCA-795-16
Comp Cams Valve Locks 10* CCA-614-16

lt1-xjs

You have to be careful which lock arrangement you use when running self aligning rockers. The rocker will hit the retainer and not the valve.

BALLSS

Agree on watching what retainer/lock you use as on SA RR the "ears" can contact the locks so you don't want that

I had the Crane 3/8" SA 1:6 RR "Gold Narrow Body" (IIRC same ones as GMPP RR) using Comp 987 springs with 10 degree locks on an older build I had and there was clear evidence some of the "ears" (the washers on the side of the roller tip of the Crane RR) hit the locks

You will see if this is a issue with the Pac 1518's once you put the 1st spring on. If the PAC are like the comp 918's I seriously doubt there will be a issue

My $.02 on the push rods is use .080 thick wall PR. I went with the 5/16" Trick Flow hardened ones but I run guide plates and NSA RR

the thing about the thicker .080 wall PR is they don't flex like stock ones do. If you ever saw that you tube video in slo mo where a SBC is running hard you see the PR & springs going ape shiat so a stronger PR, IMHO, is better.

350 groundpounder

iTrader: (5)

Thanks for all the info guys. Okay i just won the GM 1.6 roller rockers off ebay for $225. So im going to use these rr's with 3/8 arp rocker studs. So i need a spring that works with these roller rockers. I hope the pac springs will work. I believe these rr's fit under the stock valve covers without any modification too.

BALLSS

The Crane 3/8" RR do fit under stock VC. IIRC the GM ones are Crane

350 groundpounder

iTrader: (5)

Can i run the .080 thick trick flow PR's with the 3/8 SA RR's. If i can i certainly will. And im assuming the arp 3/8 studs will be better than the stock rocker studs but not quite as strong as the 7/16 studs but im running a small turd cam so it shouldnt be a prob with the 3/8 studs.

ACE1252

The locks and retainers I used in my setup may not work for SA rockers(good catch gents, I didn't think about that). Here is the amount of valve tip showing with the 1518's and hardware I mentioned above installed.....
http://ace1252.com/images/CC503_Buil..._valve_002.JPG

Here is a better shot(1518 and hardware above)....
http://ace1252.com/images/CC503_Buil..._valve_001.JPG

Here is the stock spring and retainer.....
http://ace1252.com/images/CC503_Buil...alve_edges.JPG

Appears to be a big difference in the amount of tip showing between them when looking from the top.

lt1-xjs

I think the 648-16 lock might work, not sure. It would give a little more install height than the stock lock.

BALLSS

yes, these.

http://www.summitracing.com/parts/cca-7608-16

and get new valve stem seals. FelPro are fine. Most auto part stores should have them

or you can buy these

http://www.summitracing.com/parts/lun-7856216

350 groundpounder

iTrader: (5)

Thanks for the info guys. I still should measure for the correct pushrod length, i like either those comps or the trickflows. Could i get away with just doing new valve seals at 99k miles or should i get a valve job?