Retarding the cam will improve top end HP but you will lose bottom end torque due to the reduced cranking pressure. I am pretty sure the degrees being measured are crank rotation, and not cam rotation. When I set my cam up, the wheel was on the crank, and I was watching a pointer on the block. I used an offset bushing, and simply drilled out the hole on the crank gear, and installed the proper color offset bushing, and it was done. The bushings were color coded as per offset. These are very fine adjustments we are talking about, and I think one tooth is too much.

Lou, I think I read your post wrong? Did you suggest that the intake lobes should be bigger? I have always heard the other way around. Is this the latest cam theory, that the intakes should be bigger? One of the reasons I didn't buy a Comp cam for my 360 is that most of their cams were symetrical profiles for some reason.

Jess, I wasn't suggesting you were benefiting in some way from your endorsement. And it is arrogance only if he won't give you references of some kind, which you say he will gladly do. "Just trust me" isn't good enough. However, testimonials such as you say are readily available from his customers are the best form of assurance that you are going to get what you paid for, and are wanting to accomplish.

Sam

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You read it right, Sam. Slant 6 does not = V8. Exh ports on a Slant flow much higher as a percentage of intake compared with V8s, and we have a highly undersquare engine (4.125" stroke X 3.4" bore), so cam requirements are different. More intake than exhaust is what you need.

Actually, for a V8 mopar, I've heard the longer exh duration only helps on stock log manifold motors, and is worse on a header motor.

Bren, I would put the cam back to straight up using bushings, which should drop your cranking pressure down to 200 or lower, which should work with pump gas if you're really careful with the timing curve. Most people say 180 is the max, but it depends on how careful you are with ign timing. I have run 210 cranking on 92 octane with no damage on a mid 15 sec 225.

Lou

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Home of Slant6-powered fun machines since 1988

But since he has more cylinder pressure than he can *use* at low RPM, its not really going to be a problem IMO. When people lose enough low-end to be annoyed, its generally because they're trying to take a stock engine and stuff a much bigger cam in it to get a power gain. Stock compression ratios are usually lower than "advertised" anyway, so you wind up with an engine that has an effective 5:1 ratio at low speed, and life is bad. That's not going to happen here with a true static CR of over 10:1.
I think its more of a slant-6 specific thing. I live (mostly) in the Mopar B/RB engine world, and there you have exhaust and intake ports that flow somewhat comparably. In stock and mild build applications, the limiting factor tends to be exhaust manifolding, so for example the Magnum/TNT/Super Commando engines of the 60s got dual-pattern cams with more lift AND duration on the exhaust side. But when you go to headers and big exhaust, the Mopar Performance cams like the "484" and the "509" (which also date back pretty far, at least to the 'Direct Connection' era) become single-pattern. And modern cams like Comp and Hughes for those engines are still either single-pattern or have more duration on the exhaust side, depending on the applicaiton. But the slant is a different beast, and as I understand it the intake side actually starts limiting things first, and its at the head port level not the manifold level.

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I have the schneider cam mentioned for use with the engine thats going into my '66 barracuda drag car. The salesman told me that the cam is actually 550/550 on both sides just to clarify that. And I believe the duration comes in at 258/262 @ .050, I have the cam card if anyone else would like to know further about the specs on this cam.

I talked to Mike Jeffery and he states my cam is a great choice for what Im doing with it. And for my goals he stated that around 12:5:1 will be the ideal compression for what I want to accomplish and should work excellent with that cam. Just my 2 pennies worth, hope it helps.

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Barret-Jackson: Ruining the car hobby for everyone!

Picked up some cam bushings today and installed the correct one to move the advanced timing back to straight up which according to the cam card, its 14* @50. (used a degree wheel)
Before touching anything I tested the compression and found that it higher than before. (240psi) Moved the cam and it didn't drop that much. Dropped to 220psi. I haven't put the motor back together at this point.

P.S. I also tried the timing 6* retarded and the pressure didn't drop below 215-220.
I noticed the valve lash was .019-.020. Before it was .016 same temp. I am thinking about tightening it up a bit and trying the test again. How tight do you think I can go? The Cam Card recommends .020 on both.

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67Cuda,FAST EZEFI,340cu,CR=10.25,RollerCam&Rocker (XR268HR,#20-810-9)(#1622-16)(EddyRPM#60779,#7576), (MSD6AL,#6425) A904, GearVendorsOD, 8 1/4,3.55:1, ClassicAir

Looks like you are the right track.

I would try retarding it some more and see whats up.....

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Yeah....Im the one who destroyed this rare, vintage automobile.....

Sandy you just missed my edit.

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67Cuda,FAST EZEFI,340cu,CR=10.25,RollerCam&Rocker (XR268HR,#20-810-9)(#1622-16)(EddyRPM#60779,#7576), (MSD6AL,#6425) A904, GearVendorsOD, 8 1/4,3.55:1, ClassicAir

readings taken in crank or cam degrees? it has to be in crank degrees. If you measured that in cam degrees go 2x

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Juan Ignacio Caino

Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.

Bren,

If the cranking compression went up then the cam was more advanced than before.

Are you sure you got the cam you paid for? Have you used a degree wheel to check the actual opening and closing points and calculated the duration? I'm curious to know the intake closing point most of all, but the opening point would be helpful too.

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Joshua

Crank degrees. The first bushing I tried was way to far retarded. I took a compression reading anyway (215-220). I moved it backup to what the Cam card says and the pressure was about the same.(220psi)
I am going to tighten the valve lash down tomorrow and retest.

Just read Joshie's post.
It seems that some are misunderstanding what I am saying. The pressure has gone down. 2 months ago the reading where 225psi @ .016 valve lash cold. Today before making any adjustments its starting point was 240psi. I was surprized to see that it went up and I hadn't changed anything. I didn't think to check valve lash at that point, I just dismissed it as the rings had more miles and where sealing better. I then moved the cam timing and the psi dropped from 240 to 220psi. moving it more really didn't drop it that much more.

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67Cuda,FAST EZEFI,340cu,CR=10.25,RollerCam&Rocker (XR268HR,#20-810-9)(#1622-16)(EddyRPM#60779,#7576), (MSD6AL,#6425) A904, GearVendorsOD, 8 1/4,3.55:1, ClassicAir

Seems to me......

Installing the cam at the recommended specs got you closer to the compression numbers you want.

......but the numbers are not low enough for 91 octane gas.

.......I conclude you need a cam that will create valve events that lower your cranking pressure to around 180-190.

Decrease lobe separation or increase overlap.

One idea would be to increase exhaust duration which might help with the somewhat restrictive setup you have now.

........keep in mind I dont know my ass from a hole in the ground about cams.

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Yeah....Im the one who destroyed this rare, vintage automobile.....

I got it right the first time (ring sealing improvement guess included)

well, try to tighten up all the lashes, maybe you'll "bleed" some of that excess of pressure. My cam (violent ramp profile) went cranking pressure low bottom when tightening from .20 mm (original specs from cam grinder) to .08 mm/ 0.1 mm. I lost like 50 PSI of cranking pressure on each cyl. Dropped from 170~80 to 120~30. Then I readjusted to .15 in .30 ex (mm) and settled for 145~155

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Juan Ignacio Caino

Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.

If I had to guess, Sandy's a** looks like a hole in the ground. I believe Sandy is on the right track.
I would have liked to buy a cam with these spec but to get one at a reasonable price is hard to find.
244 I 248E 110 lobe sep .518 lift.
The cam I just bought from Erson group buy is...
250 250@50 110 lobe sep .562 lift.

I could have went with a
246I 250E 110 lobe sep .510 lift.
but I really didn't want to go down in the lift deptment.

The schneidercam
Cam part #:14506 Grind#:292-96F
Specs:
292/296 Adv. Duration
258/262 @ .050
0.550/0.500 lift (minus lash)
Lobe sep.- 108*

that was recommended has been shot down by many including a tech at Crane Cam who offered advice even though he had not cam for sale for the slant6. They all say basicly the same thing. That cam won't reduce your cylinder pressure enough and will raise your power band to high.

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67Cuda,FAST EZEFI,340cu,CR=10.25,RollerCam&Rocker (XR268HR,#20-810-9)(#1622-16)(EddyRPM#60779,#7576), (MSD6AL,#6425) A904, GearVendorsOD, 8 1/4,3.55:1, ClassicAir

If this don't fix it I'll plumb in a waterfall.

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67Cuda,FAST EZEFI,340cu,CR=10.25,RollerCam&Rocker (XR268HR,#20-810-9)(#1622-16)(EddyRPM#60779,#7576), (MSD6AL,#6425) A904, GearVendorsOD, 8 1/4,3.55:1, ClassicAir

Stack the head gaskets!!