cam experts

i know we have a few in here. my engine is already built and on the stand, and i really dont have the money but i may want to reconfigure my valve train. i need to tear the motor back apart anyway because i forgot i need to get it balanced. yes you heard me right, i got so excited to build it, i did, and then a year later i was staring at it while having a cigarette in the garage and it hit me that i never balanced the rotating assy. silly me.

anyway back on topic. i feel i went conservative on the cam duration wise, part of this was not by choice as my stock vortec heads limit lift, and cams at those lift ranges dont seem to have duration. i also have no idea what im doing whenn it comes to cams really. ive read theory until my brain wont accept anymore and i still have no idea what to choose. i am especially confused by a stroked 305s needs. i plan on getting the beehive springs and proper seals to allow me to run above 0.500 lift if necessary.

heres what im dealing with
stroked 0.030 305, making it a 334, 3.77 bore and 3.75 stroke
vortec 062 heads 1.94/1.50 64cc chambers
with the right head gasket i got the squish to 0.043" and static CR of 9.28
comp magnum roller tip 1.52 ratio rockers (stamped steel ones, nothing fancy)
edelbrok performer intake and 600cfm holley vacuum secondary
patriot shorty headers 1.5" primaries 2.5" collector, probably into a 2.25" Y into a 3" single
i didnt have money for a roller cam so i am setup for a flat tappet hydraulic.
i will be using a 700r4 a 3.42 with a 25-26" tire. i need a good torque curve, but i dont want it to fall flat at high rpm, i would like this motor to pull hard untill 5-5500 rpm.

heres is the current kit installed.
http://www.compperformancegroupstores.com/store/merchant.mvc?Screen=PROD&Store_Code=CC&Product_Code=CL12-256-4&Category_Code=

cam card
http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=91&sb=2

Ok, looks like we're going to peg the horsepower at 328 @ 5000 and torque of 387 @ 3500. Over 350 ft.lbs from idle to 5500 which is nice. 5500 rpm is still shows 320hp, but it's just dead after 5500. Also, your BMEP which is the combustion chamber pressure just before ignition is low, peaking at 177. A well built street engine with iron heads should shoot for 180-190, aluminum heads are safe at 200. Your volumetric efficiency peaks at 86% at 4000 rpm, which means you're building your efficiency early, ideally you want your peak volumetric efficiency for a street engineas close to your red line as you can, so you're not wasting the extra cubes up high.

If you want a single profile that will drop right in with your lifters and everything the 12-223-4 cam would get you over 350hp and move your torque to 370 at 4K and 4500 with peak volumetric efficiency of 89% at 5K, but still 88% at 5500. However with a lift of 495, you'll need LS2 valve springs with comp retainers to keep from maxing out and bending something, and that's another $100. The 12-324-2 is extremely similar, hot quite as aggressive with only 483 lift. Those are my two best guesses for you.

much appreciated artos. what software did you use?

Dyno 2K3, it can be a bit optimistic, but it's great for at least measuring the differences between components and how effective certain changes can be.

i use the exact same program, i probably came up with 10 different viable options from the cam iterator and just confused myself, i may have even come uip with a similar cam. i need to go back to my records and compare and contrast.

would it be worthwhile to have the head milled a bit to increase static cr and bmep?  was hoping to just pull the crank and pistons out the bottom end to get balanced, that way i wouldnt have to touch the head gaskets.

it looks like 12-223-4 is a solid lifter grind, just fyi

Oops, I have this whole list of cams and was going through playing with them, I can't remember what the naming breakdown is anymore. 2XX must be hydraulic flat, 3XX must be solid flad, 4xx would probably be hydraulic roller and 5XX solid roller, but I can check again when I get home. The Cam iterator is only good for giving you an idea of what to look for, and it's going to go nuts on the exhaust side of any SBC heads. I have it on a FAST computer at home, so I can run 6 sessions at once, each running right about 1K iterations a minute, so I can let it run for a while tonight, see what it comes up with and check that against the cam lists, see if they come up with something better than I could off top of my head.

How are you going to get the pistons out the bottom of the block?

How are you going to get the pistons out the bottom of the block?

this is a product of working on way to many types of engines and forgetting whats what. lol, disregard that please, i feel like an idiot, im applying dirtbike geometry to a sbc in my head.

i look forward to more cam talk. thoughts on milling the head then?

also forgot to mention im using a 2200 stall

Milling the heads would only be workable if you're going to run 91 octane. I would never try and run 10:1 on iron heads with anything less. Aluminum heads can take 10:1 all day every day because they disipate heat faster, so the chances of detonation are much lower. I'll get DD fired up right now and see what it says.

Ah, found a cool one, Comp 12-322-4, 228 and 236 one a 110 LSA with .474 max lift on both lobes, should be just fine on your stock heads, but you'll want to double check. 352hp @ 5500 and 369lb/ft from 4K to 4500. The BMEP is under 170 and your FMEP and IMEP both look a little low, so you could bump compression to 9.75 pretty safely, which adds 8hp and 7 ft/lbs at the peaks. It would be happy hitting a redline of 6K, but don't push it past that or you'll start to get a littel hot under the collar with that set-up. Best of all, you could easily get that little bump in compression with a thinner gasket. Fel-Pro makes a GREAT one for 305s that has a compressed thickness of .015 but a bore of 4.1. It's what I'm using on mine to get compression to right about 10.17.

pistons are 0.015 in the hole putting me at 0.043 quench with the current 0.028 gaskets (4.13' bore). whats a safe minimum? a 0.015 gasket would put me at 0.030, which irrc is the ragged edge. i have no problem running 91, hell my dd requires it.

 i just found a copy of dd2003 and installed it, im reassembling all my info as i seem to have lost everything when i reformatted last time. ill mess around with some numbers. thanks again artos.

Always glad to help. yeah, I didn't realize the block was decked .010 or you were running slightly taller pistons. I wouldn't go much tighter on quench. I've run .035 with these gaskets and aluminum heads, but on iron heads anything south of .040 is really pushing your luck. I could e-mail you an archive with all the cam and head files I have if you want.

must be the stroker pistons because the block in untouched. i would like that archive thanks.

I'll pull your email off your profile when I get home tonight, don't want you picking up a bunch of spam.

i came up with a further improvement, but it wants a lot of exhaust duration in comparison with intake, so the cam would be a custom grind, which im not going to do. i bumped the comp up to 9.8.  BMEP in the high 170s from 3 - 5k peaking to 180.1 at 4k.  373hp at 5500 dropping to 365 at 6k, torque peaks 394ftlb at 4k, dropping to 356 at 5k, and 320 at 6k. and my baselines were lower than yours, we obviously have a slightly different configuration.

.470 lift
252/286
110 lsa

what the hell is with that duration spread?

What settings are you using for intake manifold and exhaust? That seems awfully high, no offense.

I mentioned it earlier, SBC heads are designed with a real disadvantage on the exhaust side. It just wasn't known how important the exhaust flow is back in the 50s when they started designing the original SBC. Better exhaust design should be credited for about half of the gains between the gen 1 and 2 SBC and the LS series of engines.

turns out i had the cam profile set to aggressive at 3.7, i let it calculate with adv. and 0.050 numbers for an xtreme energy flat hydraulic, and it came up with 2.68. that knocked my numbers down to 359hp at 5500, and 383tq at 4k, with bmep at 175.1. im using "dual plane high flow" intake and "small-tube headers with mufflers" exhaust.  600cfm at 1.5"hg carb. it is supposed to be 1.5" correct?

im using this chart for head flow, claimed 062 numbers. at 28" h2o, correct?
Valve Lift   Intake   Exhaust
.100   70   48
.200   139   101
.300   190   121
.400   227   140
.500   239   147
.600   229   151


either way it makes more power and pressure than the 12-322-4 in my combo... none taken

Definitely kick your intake down to standard flow dual plane. You have to remember this program is designed around really high horsepower engines that can flow absurd amounts. 1.5" is right for a four barrel carb, that's how they've decided to rate them. And for stock L31 heads, which should be both the 062 and 992, I have:

.1     59     50
.2     118   111
.3     177   148
.4     217   160
.5     226   164

I have other files for the 441, 462, 882, 041, L98, LT1, LT4, 855 vortec and the 372 heads, so that should be the right file.

whats the intake centerline on the 322 i cant find a cam card for it.

It's comp, so probably 108, they like to run everything 2-4 degrees advanced for whatever reason.