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Syn77 09-05-2012 07:47 PM

valvespring upgrade questions
So I know I'm gonna get chewed out for this but my cam went flat in my truck it wasn't broken in right so i was gonna get a summit cam and lifter kit for like 100 bucks but I seen a lunati voodoo 60102 for 130 so I said OK I knew I was gonna need springs. This is going in my 77 k10
355 th350 NP 203 373 gears
Not sure on compression
Performer intake edele
Hedman headers
Edele 1406
Msd wires and coil
624 heads getting better when time permits
So I looked up the spring kit for and I didn't know if they were to big for my crappy 624 heads the size of the factory ones I think are like 1.250 and the new springs are a little bit bigger like 1.266
So my questions are will they work and will I need hardened pusgrods and since its a higher lift cam then my stock one will the push need to be longer or shorter thx guysguys

spinn 09-05-2012 08:28 PM

It went flat. That cam may like 9:1 compression. What stall are you using? A mild cam will tolerate stock pushrods even if the geomtry is not exact. You can check it with a length checking adjustable pushrod. The installed height is for rated seat pressure, as long as you have open clearance it should be fine.

My 305 c10 worked well with a performer cam, 906 vortec heads , performer intake, AVS 650, 3.73 gears, 3000 stall , 28" tire, headers, msd ignition. It is a heavy truck and cannot sacrifice low end. Save for a supercharger 6 psi is worth ever penny.

Do a search on engine break in. Make sure to prime the engine oil system while turning crank by hand. Look for oil at all rockers. 09-05-2012 09:19 PM

I haven't looked up the cams you intend to use. But, anytime you change valve springs. You must know what your installed height is. What the spring pressure is at that height and adjust, if possible, to get the correct specs. This will include. Different retainers (no rotators!) available in many heights. Valve locks, in many groove heights. shims from .005 thru .060" in correct diameters for your particular heads. Pockets can usually be cut for larger springs. Tho yours are thin and not much material to work with.

Then you must provide stem seal to retainer clearance and seal to spring clearance, then provide for over the cam nose pressure and stack height.

Not for the hobbyist with no tools and experience.. Thats why I have over twenty stocked drawers with the afore mentioned parts and a large shop full of tools.

Better to have it done correctly than to loose a flat tappet cam/lifters and bottom end bearings. I see this almost every week lately..

Syn77 09-05-2012 09:19 PM

Ya my dads friend said he broke it in but I was wondering if i should upgrade to a 2400 stall or something I have a pretty decent size transcooler on do I didn't think it would be a h****le

Syn77 09-05-2012 11:32 PM

The kit comes with new retainers locks and stuff but I was wonder how to check the installed height and stuff I've takern them apart and stuff but never really checked that stuff do u use calipers or something 09-06-2012 04:48 AM

You can use calipers. The cheapest way is get a 6" digital vernier from Harbor Freight. Usually around $10.00. They work well for this situation.

The best is a spring "Height mike" available from shop suppliers. Or even Summit.

Spring "Kits" for heads are hit/miss. Unless they are assembled for your specific heads. It is up to the builder to correct the specs.. GM heads use different spring pocket heights. For rotators on exhaust. Most universal kits don't allow for this.

Several times a year a customer will bring me heads that have aftermkt springs/retainers installed. Complete with a "miss". I check the springs/height and invariably there are no spring shims on the exhaust side. This results in about 30 lb. of spring pressure.

SSedan64 09-06-2012 07:06 AM

Valve Spring Installation
Valve Spring Installation

Syn77 09-06-2012 11:08 AM

So if the kits usually don't work will z28 springs and some shims work 09-06-2012 02:53 PM

Z/28 is now a catch all phrase for stock dimension SBC moderate performance springs. These can be anything. The specs are all over the place. I have seen them at 87 lbs. to 110 lbs. at 1.720". Depends on the retailer and must be checked..

Syn77 09-06-2012 11:33 PM

I found some z28 springs 1.250 good to. 525 from Scot and diggey will these work

Syn77 09-07-2012 02:20 AM

I found some z28 springs 1.250 good to. 525 from Scot and diggey will these work

cdminter59 09-07-2012 07:34 AM

valvespring upgrade questions
Lunati recommended valve springs. #73943K1, OD. 1.266, Spring Rate 462 lbs., ID. 0.883, Inner damper, fits 11/32 valve stem diameter. Talk to a machinist for a similar spring replacement. You may not have 11/32 valve stems. Valve seals #78501-16. Another thing I hope you have had those heads checked by a machinist according to threads on the valve seats crack easily. GM added an addition exhaust crossover (more heat) causes the cracks. Find a set of 73-early 74 76cc heads. Replacement GM heads 3973487,3998993. If you you want a good set of heads check these out. Can't beat the price! Summit Racing SUM-152123 - Summit Racing® Cast Iron Cylinder Heads for Small Chevy - Overview -

Syn77 09-07-2012 08:13 AM

They were checked just got back from the machine shop with the block when I bought the thing a while ago it doesn't many miles if even 2000 at this seems like a lot of trouble should I just hold the cam a stock replacement get some vortecs and intake or just run it if I can with some other springs

spinn 09-07-2012 09:59 AM

Vortec heads are great work horses. If you drive and use it as a service vehicle they offer daily driver performance and reliability. My 906 vortec heads were $200 for the pair. With that, the yard let me grab 16 beehive ls6 springs from series 2 v6 engines. Some forum member passed on this head recipe as good. It worked better than many aftermarket head packages. The springs are around 300 open, 96 closed, and have the small retainers. The factory vortec roller cam is around .420 lift and if you use it with a performer flat cam it works great. My oppinion is that the performer cam and vortec heads is the best , cheapest way to get the most for the least. No head mods nesscary. If 67cc is to big go to napa and have the machinest do the milling on the side or after hours. It will save you some cash and doesnt hurt to ask. My heads were milled to 60 cc for less than $80.

You can find a 3.73 gear set for cheap to. A 3000 stall would be a acceptable road peice. Then you could do nice burnouts and seat planting launches.

cdminter59 09-07-2012 10:03 AM

valvespring upgrade questions
If that's the cam you want by all means run it. Get the cam and take the heads back to the machinist with Part# 73943K1 for the spring kit. Like I said he may know a replacement spring that will work with valves. This is the most cost effective way. If you can find a set of Vortec's that would be the best thing to do. Most likely you have dished pistons and they would give you a boost in compression. About 50hp from the heads alone. You'd still need the valve springs for the Vortec's and cut the valve guide bosses for the higher lift cam. You would feel the difference. I don't think you would get no more than 300hp out of the 624's.

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