I am pulling the 383 out of my car in an effort to fix the things that did not get done the first time around. Two reasons for them not getting done. 1)I was leaving for college in 2 days and did not want to leave a non-running car at home. 2)Money was low.(Isn't it always? smile.gif ) So here is what I am going to be running:

383 small block
Keith Black hyper pistons 19cc D-dish yeilding 9.6:1 compression with a .015" head gasket
6.0" Eagle SIR rods
Scat 9000 series 3.75" stroke crank
3310-6 750cfm Holley
Weiand Stealth intake
WP Sportsman II heads w/Manley Pro Flo valves
Comp XE262 218/224@.050" or XE268 224/230@.050" lift cam
using Crane 1.5 ratio roller tip rockers
1-3/4" primary tube Hedman headers
2-1/2" Flowmaster exhaust system
3.31 geared 12 bolt posi
Supercased M-20
Centerforce Dual Friction clutch
Hayes steel flywheel
68 NovaSS fighting weight of 3650lb on the starting line


The items in bold are the ones that will be changing. Currently the engine has 9.1:1 compression, a Crane 218/218@.050" "3/4 Race cam", Edelbrock Performer RPM intake and Zoom stock clutch. I am not pleased with the cars current low end torque output. I really think either of the Comp XE cams is going to increase my low end torque. I want to hit the 12's with this new engine combo, but the car is 95% street 5% track. If the small cam can do it I'd rather use it. If not, maybe go with the bigger cam, I'm pretty sure it will hit the 12's. I have also toyed with the idea of the small cam plus some spray. Just a little shot should get me in the 12's with the small cam, and I get my smooth low end torque and driveability. Which cam would work best do you think?

I don't get it. My 383 has plenty of torque. :D
Must be the extra 2 pts of compression.
Our cars are similar so:

As a guess, your old combo had to little compression for that cam.
And from what I've heard, the stealth and RPM are pretty close in performance. Although I've heard of some quality issues with the newer Stealth's.
I checked the DCR using your listed CR. 8.0 for the 268 and 8.17 for the 262.
Either cam should be fine. I'd think the 268 would give you more HP though. And unless you want a dead stock idle, the 268 would be better. Especially with stock SPIIs' lazy exh port.
You might consider the HE268. Been a few discussions here about that cam actually being better than the small XE's. Check Comps site. They have dyno tests with all three cams on their site.

Yes, I was going to mention using the good old CC 268HE cam..

pdq67

That 274H06 that is in there now should make brutal torque starting about 1800 rpms or so. Either of the comp grinds would work well too, but I don't think the cam is your problem.

hehe Don't get me wrong guys, once the engine gets going, about 1800rpm or so its a tiger. It will spin my 265s even with my Caltracs at a 2000rpm launch. But I don't want to be constantly clutching it at 1300rpm to keep running with traffic. I have to get it apart to fix the compression problem. Thats not helping my cam any as it is. 9.1:1 is pretty low for the 274/274 grind. See...problem is I want the same brutal torque from idle to about 6000.(I think my big block car has spoiled me.) lol No seriously. I am really leaning to the XE262 now, I think I will like smaller better than bigger in this case.

I thought about the CC 268HE cam, but thought with my heads, since they flow well up to .500" lift and above, why not go with as much lift as possible without getting the cam too big?

"Either of the comp grinds would work well too, but I don't think the cam is your problem."
Suggestions on what else it might be? I think what I am feeling is just the cam being a hair bigger than I would like in conjunction with my 3.31 gears and 25" tall tires. If I had 3.55s I don't think I would notice anything at all.

A 218/218@.050 is not a big cam...especially in a 383. I guess I could see the tight lsa having some effect on the initial clutch takeup in stop and go traffic...but its still hard for me to imagine that with a 383. I use a XE268 in my 3.08 geared truck...it will idle at 500 rpms in gear no problem, and it pulls well from idle, but it really starts pulling good about 2500 rpms. How much initial and total timing are you running? Some tuning changes might make all the difference in the world in the way it runs on the street.

Remeber guys, an M20 and 3.31s is a tough start. No converter slip to multiply torque.

Do you have tall tires on the back as well?

This is what I'd do. See where the Crane is, timing-wise. Make sure it isn't retarded, at least, by using Harold's Quick and Dirty Method. If it is, then move it AND swap head gaskets.

Either Comp should work. The key is to open up the lobe separation a bit I think. 110 or 112 even with shallow first gear ratios. I'm surprised that the Crane doesn't come on a bit sooner ( which is why cam timing is mentioned), but I've never run a cam that tight. BTW, I really like the XS grind Mike Newby is moving into. Might fit the bill here quite nicely. Low end AND some revs too.

Based on the power band and intended use you describe there is no better choice than the Performer RPM IMO. I'd dump the Holley manifold in a heartbeat.

Here's a cam . . .

http://www.iskycams.com/timingchart.php?product_number=201271281&timing_chart_id=128

271/281 advertised, 221/232 duration @ 050, .465/.485" lift, 108* LSA. Perfect for your heads IMO (Sportsman II exhaust ports are a little weak and need a dual pattern cam IMO)

Using Pat Kelley's DCR program the DCR would be 7.98:1 with a 9.5:1 static CR. I think it would pull hard from 2000 to 6000 RPM in your 383.

Sorry, can't help with a clutch.

PS. the 108* LSA might be a little tight with the manual trans . . . but a 383 should make tons of TQ and would really like the tighter LSA in the midrange.

Hmmmmm.....its not an everyday driver anyway....
OK Comparing the XE262(hydraulic) and the XS262(solid) what kind of torque/hp difference would you think I'd see? I would consider going solid for 25ft*lb/25hp. For only 7....I doubt it.

BTW What's Harold's Quick and Dirty method? I did some searching and came up empty. Thanks guys.

Also, I am going to the Stealth intake to get my air cleaner off of my hood. I have heard rumors of similar performance to the RPM, but it is a chunk shorter.

Can't tell you the difference exactly. MaybeComp can. Mike Newby should be able to soon.

quick and dirty - roll the motor over by hand, stop at #6 TDC. Check the relative heights of the #1 vavles. If they are the same height off the head deck, the cam is straight up. If the intake is slightly closer to the head , it's advanced. If the exhaust valve is closer to the head deck ( measuring off the retainer to the head surface), it's retarded.

Hey, it might be the 107 lsa, which I;ve never dealt with. But if you find the cam in straight up or retarded, it might just need a little 're-phasing'.

Several things I just caught are first, the mention of Crane "3/4-Race Cam"?

This brings to mind a cam with and advertised duration up about 290 or so vs one normally at 268 to 274.. But yet still with a 218 , 050" duration b/c this was how the old cams were designed b/c they didn't have good springs and computer design programs to get the accel./H.I. thing better.

AND I do know the nostalgia cams like the old 3/4-Race are being sold b/c of that sound all us "old" guy's remember!!!

The other things are your M-20, 3.31's and stock 25" tall tires!!

My 406SB has a 292/230, .480" torque hy- cam in it but with 26.5" tall tires AND it ran like you said cruising but up above 2000/2250/2500 or so, not as low as yours!!

Check and see if your cam is a TRUE old design long advertisd duration 3/4-Race Cam and that will probably be where your drivability problem will lie!!

B/c the 268/274 cams should run great in your motor, imho!! Not a 288/294 or even up as high as a 300 cam!!!

Heck, the little old 327 motor I gave my nephew had a "Little Fireball" Crane/Cam Dynamics cam in it that was right at 268/216 or 218, .450" AND IT ran great in the little motor!!!

Call Crane up and tell them the cams PN to be sure what it actually is, otherwise, if it is a 268/274 cam, I would look for a vacuum leak or timing issues, either installed or at the distributor, as already mentioned....

pdq67

i thought 3/4 race cams had 270 duration at .050"?

no, Crane calls some of their tight lsa cams 3/4 cams. The term isn't really used anymore. I know they consider the bbc Energizer cam on a 108 lsa a "3/4 race cam".

Gene knows where I'm talking about...

But I am talking about '50's and '60's cam's, not the newer one's UNLESS they are made the old design way..

General Kinetics made two cams years ago;

1. 290/218, 114/?, .450" lift. (I bought this one first from Hollywood Sam's in Detroit years ago).

2. 270/216, 110/?, .454" lift. (Then I took the first cam back and exchanged it for this one and got a set of lifters to sweeten the exchange. It's in the 327 I gave my nephew)..

I wrote a note to G/K asking what the diff. was between them and got an answer back that said it was a lobe center thing that couldn't be explained in a short note... Still have the note somewhere???

Anyway, that's why I brought up the advertised duration thing..

pdq67

PS., and didn't Crane end up later with what was left of G/K???