I have done somereading and it seems to me the 2040 would be a good choice. I was also contemplating getting the stamped steel 1.6 rockers from summit. will comp 981 srpings do the job fine? what else will I need? I am trying to keep cost down. Push rods? timing chain? Keep in mind my car had fairly low miles. Will the 2040 have any lopiness to it? I would love it if it did.

 

I've used it's bigger brother the 2050 a couple of times. It had a slighly choppy idle. The 2040 is probably a pretty smooth idler. I think your cam's got about 210/216* duration on a 112* LSA, if memory serves.

Stock length pushrods will work just fine if they're for a flat tappet cam- 7.8" length. I've used the Summit $22 cheapie hardened pushrods in many mild performance motors and they work just fine whether you run guideplates or self-aligning rocker arms.

Timing chain is nothing special- just about anything will do that's built for a SBC flat tappet cam, but if you're not dropping around $40+ on a chain you're probably not getting very good quality. If you are converting over from a factory roller cam the flat tappet style timing chain is a bolt-on. You would not reinstall the factory roller cam retaining plate. The roller cam "spider" and lifter retainers would likewise not be reused.

Rocker arms I wouldn't do 1.6s unless you know that your heads can take the added lift. If you are pushing over .460-.470" maximum lift on a stock head you're asking for trouble with the retainers hitting the guides/seals (has nothing to do with the springs binding up). Take your maximum lift with 1.5 rockers (listed on the cam card), multiply by 16 then divide by 15 and that will be your lift with the higher ratio rockers. For example:

.440" lift with 1.5s = .469" lift with 1.6s DANGEROUS with stock heads that haven't had the guides machined down.
.440 x 16 = 7.04. 7040 / 15 = .469"

And you'll have to find out if you need self-centering rocker arms or not. If you need self-centering rockers your choices are more limited and expensive. Non-self-centering rockers are far more common and slightly less expensive. This will be determined by what you find when you take off the valve covers. If your engine currently uses self-aligning rockers that's probably what you will keep using unless you have the heads machined for screw-in studs and guideplates. If it's got non-self-aligning type then that's the style you'll keep using. Any rocker with a roller tip is usually non-self aligning except for some models of Crane roller rockers and a few others.

The Comp Cams 981 springs will be drop-in replacement for your stock springs. No machining required. If your heads use exhaust valve rotator/retainers I'd recommend you keep using them. If you really can't stomach that then put a .050" shim into every exhaust spring pocket before you put it back together to get the installed height back roughly right with standard retainers.

 

thanks for the reply. The car is an 85' LB9 btw and is not a roller block. and it has the better cam already. I was also planing on upgrading to an 89' computer and start tuning. I was also planning on a 2200 stall, or somthing along those lines.... I do have a fully ported TPI w/ SLP runners. I also have headers and will soon have 3" all the way back as well. would a benifit more from a slightly larger cam takeing these things into consideration?(larger than the compucam 2040) actually im now looking at the self aligning federal morgul 1.6 stamped rockers for about 80 bucks at www.sdpc2000.com ..... i would like some more opinions on max lift for stock heads with no modifications other than comp 981 springs. If the heads cant handle it, I will scrap the 1.6 rocker idea.

 

I just remembered hearing this a while ago and found it in a search. Would this combination of manley springs (22410-16) and retainers(23652-16) prevent the need for guide clearancing?
here is a thread: https://www.thirdgen.org/techbb2/sho...hreadid=187656

 

Might work but here's the rub...... self-aligning rockers have little "lips" that stick down slightly on either side of the valve stem to prevent the tip of the rocker moving side-to-side on the valve stem. The retainers mentioned in that thread more the retainer up by .050" giving you the extra retainer-to-guide clearnace you need BUT......... the little "lips" on the self-aligning rockers MIGHT now contact the top of the retainer, not allowing the center of the rocker arm to push directly on the valve stem tip. Bad bad bad if that's the case. You have no choice but to install it and see if you can go that way.

Additionally, if +.050" retainer height will work for you there is a much easier way to achieve it. Comp and Crane both sell retainer locks (the 2 little pie shaped wedged that lock the retainer to the valve stem) in +.050" installed height versions. They will do the same thing with your stock retainers as the special retainers mentioned in the thread but for a lot less money ($22).

And if you choose to raise your retainers .050" by EITHER means you don't have to choose different valve springs. Many companies sell valve spring shims in various thicknesses. Put a .050" thick shim in your stock valve spring pocket and it will raise you valve spring by the same .050" you raised the retainer and your installed height will remain the same, allowing you to continue to run the same springs you originally intended.