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Old 01-30-2007, 08:41 PM
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Another Cam selection question

All right, here's another cam question. I to am looking for a good cam to run. I've gotten all kinds of suggestions from different cam manufactures So here we go:
SBC350 basically stock bottom end
9.5-1 compression
Vortec heads, with some port work done on the exhaust side, max lift 480.
Edelbrock RPM Airgap
Holley 750 Vac Sec.
th350 with around 2500+ stall
3:08 gears. May change to 3:37s in the future?
And here's the actual flow numbers for my heads. Mine are the one's on the left, under the before column. Anybody care to take a stab at it? Thanks


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Last edited by NWayne; 01-30-2007 at 09:10 PM.
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Old 01-30-2007, 09:49 PM
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Ok, nobody else has barked so I guess I will, Comp Cams XE268H....now that being said, are you guessing at the compression or are you sure? I,d change the rear gears to 3.73's ....SOON and ditch the 750 for a 650. The guys at Superior could'nt give you a combo??? They've built a ton of hipo engines.
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Old 01-30-2007, 10:11 PM
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Quote:
Originally Posted by 327NUT
Ok, nobody else has barked so I guess I will, Comp Cams XE268H....now that being said, are you guessing at the compression or are you sure? I,d change the rear gears to 3.73's ....SOON and ditch the 750 for a 650. The guys at Superior could'nt give you a combo??? They've built a ton of hipo engines.

I'd change the gears and try tuning it with the 750, before trying a smaller carb.
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Old 01-30-2007, 10:15 PM
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224* single pattern, 108 LSA, 1.6 rockers

assumes good scavenging

keep the 750 vac sec.

Your heads are close to this =

http://www.popularhotrodding.com/eng...ock/index.html
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Old 01-30-2007, 10:33 PM
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Quote:
Originally Posted by xntrik
224* single pattern, 108 LSA, 1.6 rockers

assumes good scavenging

keep the 750 vac sec.

Your heads are close to this =

http://www.popularhotrodding.com/eng...ock/index.html
Yea, I was thinking of going with a single pattern cam. The ones I've been looking at are the Lunati Bracket master II 230@.50, 480 lift LSA 109, and a doug herbert cam with roughly the same specs. But the LSA on the doug herbert is 110.


I like the way you think Xntrik. Where are you in AR? I'm originaly from the LR area.
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Old 01-30-2007, 10:38 PM
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Quote:
Originally Posted by 327NUT
Ok, nobody else has barked so I guess I will, Comp Cams XE268H....now that being said, are you guessing at the compression or are you sure? I,d change the rear gears to 3.73's ....SOON and ditch the 750 for a 650. The guys at Superior could'nt give you a combo??? They've built a ton of hipo engines.
I bought these heads from a friend who had the work done at superior. This combo was going on a 406 before they came to me.
I'm trying to stick with the 750 before I drop down, since it's not costing me anything.
The gears will eventually be swapped, but for now they will have to stay. I'm on a budget.

Last edited by NWayne; 01-30-2007 at 10:50 PM.
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Old 01-30-2007, 10:38 PM
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Quote:
Originally Posted by NWayne
Yea, I was thinking of going with a single pattern cam. The ones I've been looking at are the Lunati Bracket master II 230@.50, 480 lift LSA 109, and a doug herbert cam with roughly the same specs. But the LSA on the doug herbert is 110.


I like the way you think Xntrik. Where are you in AR? I'm originaly from the LR area.
Up in the north mountains in Whitetown. Ya cool. It is 18* out here, snow tomorrow night..... brrrrrr.

Read that article thoroughly.

Last edited by xntrik; 01-30-2007 at 10:55 PM.
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Old 01-30-2007, 11:24 PM
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I read the article, but I don't want to have to switch to a roller cam$$$$ Plus I don't know what I would have to do to my heads to run 1.6 rockers? I'm trying to stick to what I have.
Here's a combo a little closer to what I have, #99 http://www.ryanscarpage.50megs.com/combos13.html
I was just trying to stay away from Comps and their extreme line of cams. I've heard too many bad things, and I know from past experiences they are hard on valve train components.
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Old 01-30-2007, 11:36 PM
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Quote:
Originally Posted by NWayne
I read the article, but I don't want to have to switch to a roller cam$$$$ Plus I don't know what I would have to do to my heads to run 1.6 rockers? I'm trying to stick to what I have.
Here's a combo a little closer to what I have, #99 http://www.ryanscarpage.50megs.com/combos13.html
I was just trying to stay away from Comps and their extreme line of cams. I've heard too many bad things, and I know from past experiences they are hard on valve train components.

So run a flat tappet with similar numbers. All you'll lose is a little lift. The pistons don't know what lifter is opening the valves.

Run your favorite brand, and use their armored lifters.

1.6s rockers usually fit with no problem.

I believe that 96% of the time someone has problems with a cam is that

1) they did not get the cam, lifters, pushrods, springs, as a SET from the cam manufacturer,

2) failed to follow proper procedures.

I have NEVER had a new cam go flat. Break them in with worn out 200# springs for 4 hours. The usual 20 minutes, change oil, then drive under load. Keep it between 2000 and 4000 rpm. Let the lifters take a set and slick their surfaces before you put the 300# springs on there.

Remember a 300 pound spring with 1.5 rocker arms pushes 450 pounds on the pushrod/lifter, and that is above 20,000 psi on the cam surface.

I promise you, 96% of the people are too damn lazy to change the springs, so they try to get by with the strong springs for break-in.
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Old 01-30-2007, 11:44 PM
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Quote:
Originally Posted by NWayne
I

I'm trying to stick to what I have.
Here's a combo a little closer to what I have, #99 http://www.ryanscarpage.50megs.com/combos13.html


.

Sorry, I just reread all the posts carefully.... not trying to be a butt here...

You say that this is closer to what you have???????

bigger heads
bigger carb
bigger intake
a full .5 more compression

Yes, almost identical.........
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Old 01-30-2007, 11:58 PM
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Quote:
Originally Posted by xntrik
Sorry, I just reread all the posts carefully.... not trying to be a butt here...

You say that this is closer to what you have???????

bigger heads
bigger carb
bigger intake
a full .5 more compression

Yes, almost identical.........
Yes, it's close. Heads are almost identical. Mine have had some port work done, valves are the same, compression is close to the same. Biggest difference is the double pumper. Were you looking at combo # 99?
Read it thoroughly.
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Old 01-31-2007, 12:13 AM
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Combo 99.
Combo 99 uses Vortec heads and a bigger cam than Combo 98. The heads are pocket ported, and this helps the engine to make 409 HP and 427 ft-lbs of torque. The torque peak occurs at 3500 RPM, but the power peak is at 6000 RPM. The torque peak is only at 58% of the power peak, instead of the normal 70-80%.
Displacement: 350 cu. in.
Carburetor: Holley 750 double-pumper
Heads: GM L31 Vortecs, pocket-ported, with 1.94/1.50 in. valves
Intake: Edelbrock Performer RPM Vortec
Camshaft: Comp Cams Xtreme Energy 268 hydraulic, with 0.478/0.480 in. of lift and 224/230 of duration @ 0.050 in. of lift.
Exhaust: Hedman 1 5/8 in. headers and Borla XR-1 mufflers
Distributor: HEI
Comp. Ratio: 9.4:1

MAX HP: 409 @ 6000
MAX Torque: 427 @ 3500
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Old 01-31-2007, 12:37 AM
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[QUOTE=NWayne]Yes, it's close. Heads are almost identical. Mine have had some port work done, valves are the same, compression is close to the same. Biggest difference is the double pumper. Were you looking at combo # 99?
Read it thoroughly. [/QUOTE

OhOH. late at night....... looked at the wrong one[B].........

more later...... must sleep.....
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Old 01-31-2007, 12:39 AM
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[QUOTE=xntrik]
Quote:
Originally Posted by NWayne
Yes, it's close. Heads are almost identical. Mine have had some port work done, valves are the same, compression is close to the same. Biggest difference is the double pumper. Were you looking at combo # 99?
Read it thoroughly. [/QUOTE

OhOH. late at night....... looked at the wrong one[B].........

more later...... must sleep.....
Thanks
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Old 01-31-2007, 09:54 PM
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Crane number 113801 HMV278. A little milder overall than the comp cam above. Lots of power(just as much) . nicer cruising.
another choice is Crane #100132 H278-10
I like the first one because of your weak exhaust flow ratio.
The Crane "HMV" lobe design series is more reliable than the comp extreme series.
Got to remember, Harvey Crane and Ed Iskenderian wiped the dreuling chins and changed the ***** diapers of most of the present day cam designers.
The lifters will run quiet. The lobe profile design is plenty radical.

Here is another Lunati #07101

another Isky#201271
If you choose one of these single pattern cams on tighter 108LSA be sure to degree and advance to 104intake Lobe c/L

Crane 113801 HMV278 was used with vortec heads on this motor build up and test click here Note the overall smooth powerband.
Its a good overall real world choice. Easy to live with.
The Lunati BM-II needs a minimum 2800stall converter and wont like 3.08's at all. All the above are better for you.

1.6 rockers on the intake side will be nice.
If you're going to swap rear gears go to a 3.73 or 4.10.
Going from 3.08 to 3.36 is a waste of time.
The 750VS is fine.
If you're limiting your choice to .480" lift cause you think or read some where you can run that on stock vortec heads without modification, think again. Then measure yours. I've seen as little as .450" total net guide/seal clearance even after checking that the seal was all the way on the guide on out of the box vortecs. Plan on having to shorten the valve guide boss or grind the bottom of the retainer for clearance.

Last edited by F-BIRD'88; 01-31-2007 at 10:56 PM.
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