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Discussion Starter #1
thanks for looking...

454, 2-piece oil seal, 9.5:1, 781 heads, mild port work under the valves, installed in 1965 scout, 4x4, 38 inch tires, 4 speed, 4:11 gearing, 750 vac holley, rpm airgap intake, 1.75 headers…

Need cam choices. Leaning towards the comp 270h magnum camshaft.

Any comments or suggestions?
 

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thanks for looking...

454, 2-piece oil seal, 9.5:1, 781 heads, mild port work under the valves, installed in 1965 scout, 4x4, 38 inch tires, 4 speed, 4:11 gearing, 750 vac holley, rpm airgap intake, 1.75 headers…

Need cam choices. Leaning towards the comp 270h magnum camshaft.

Any comments or suggestions?
With those tires, you will need either a stock cam or some 5.13/5.38 gears to run the 270H cam.
 

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Richard is kinda correct... That 224/224 cam isn't going to start pulling hard till about 2500 RPMs and above... RPMs vs MPH for your current setup:

RPM 1st Gear 2nd Gear 3rd Gear 4th Gear
500 5 7 9 14
600 6 9 11 17
700 8 10 12 19
800 9 12 14 22
900 10 13 16 25
1000 11 15 18 28
1100 12 16 19 30
1200 13 18 21 33
1300 14 19 23 36
1400 15 20 25 39
1500 16 22 26 41
1600 17 23 28 44
1700 18 25 30 47
1800 19 26 32 50
1900 21 28 33 52
2000 22 29 35 55
2100 23 31 37 58
2200 24 32 39 61
2300 25 34 40 63
2400 26 35 42 66
2500 27 37 44 69
2600 28 38 46 72
2700 29 40 47 74
2800 30 41 49 77
2900 31 42 51 80
3000 32 44 53 83
3100 34 45 54 85
3200 35 47 56 88
3300 36 48 58 91
3400 37 50 60 94
3500 38 51 61 96
3600 39 53 63 99
3700 40 54 65 102
3800 41 56 67 105
3900 42 57 68 107
4000 43 59 70 110
4100 44 60 72 113
4200 45 61 74 116
4300 47 63 75 118
4400 48 64 77 121
4500 49 66 79 124
4600 50 67 81 127
4700 51 69 82 129
4800 52 70 84 132
4900 53 72 86 135
5000 54 73 88 138
5100 55 75 89 140
5200 56 76 91 143
5300 57 78 93 146
5400 58 79 95 149
5500 60 80 96 151
5600 61 82 98 154
5700 62 83 100 157
5800 63 85 102 160
5900 64 86 103 162
6000 65 88 105 165
6100 66 89 107 168
6200 67 91 109 171
6300 68 92 110 173
6400 69 94 112 176
6500 70 95 114 179

It would be drivable, but feel like there are a lot of conditions when not much power available... Depending on what you are using the vehicle for...
 

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5.38 gear:

RPM 1st 2nd 3rd 4th
500 4 6 7 11
600 5 7 8 13
700 6 8 9 15
800 7 9 11 17
900 7 10 12 19
1000 8 11 13 21
1100 9 12 15 23
1200 10 13 16 25
1300 11 15 17 27
1400 12 16 19 29
1500 12 17 20 32
1600 13 18 21 34
1700 14 19 23 36
1800 15 20 24 38
1900 16 21 25 40
2000 17 22 27 42
2100 17 23 28 44
2200 18 25 29 46
2300 19 26 31 48
2400 20 27 32 50
2500 21 28 33 53
2600 22 29 35 55
2700 22 30 36 57
2800 23 31 37 59
2900 24 32 39 61
3000 25 34 40 63
3100 26 35 41 65
3200 26 36 43 67
3300 27 37 44 69
3400 28 38 46 71
3500 29 39 47 74
3600 30 40 48 76
3700 31 41 50 78
3800 31 42 51 80
3900 32 44 52 82
4000 33 45 54 84
4100 34 46 55 86
4200 35 47 56 88
4300 36 48 58 90
4400 36 49 59 92
4500 37 50 60 95
4600 38 51 62 97
4700 39 53 63 99
4800 40 54 64 101
4900 41 55 66 103
5000 41 56 67 105
5100 42 57 68 107
5200 43 58 70 109
5300 44 59 71 111
5400 45 60 72 113
5500 46 61 74 116
5600 46 63 75 118
5700 47 64 76 120
5800 48 65 78 122
5900 49 66 79 124
6000 50 67 80 126
6100 50 68 82 128
6200 51 69 83 130
6300 52 70 84 132
6400 53 72 86 134
6500 54 73 87 137

May want even bigger gear! 6's...?

http://www.andysautosport.com/learning_center/calculators/
 

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Member StraubTech sells a custom BBC 203/210 hydraulic roller that would also work better with 4.11 gearing... and better for 9.5:1 compression ratio...
 

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Discussion Starter #7
Thanks for the info guys.
The 270h has an RPM range 1500-5800 which is also nearly identical to the intake manifold.
The 268 cam moves the RPM range down a few hundred RPMs, which is also a nice choice as well.
Roller cam/lifters is a nice choice for sure, but not in the intended budget for this build at this time. Maybe later down the road it can be swapped to roller, but definitely not in the crosshairs anytime soon. –don’t worry there will be plenty of additives in the engine oil, so flat cam lobes should not be a problem.
 

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Thanks for the info guys.
The 270h has an RPM range 1500-5800 which is also nearly identical to the intake manifold.
I don't think you're understanding what we're trying to tell you here. Let's try another approach....

If you were to use this cam in a street-driven vehicle, you would likely want to use a ~27" tire and a ~3.55:1 rear gear, resulting in the car running about 113 mph @5000 rpm's.

Now, if you were to use the same cam, but changed the rear gears to 4.11's and bolted on some 38" tires, the car would go 137 mph at the same 5000 rpm's.

You would have to change the rear gears to ~5.00's with the 38" tires to get the same relationship as you would have with 27" tires.

Bottom line: You need more rear gear using the tall tires, to make the cam work at the engine speeds where it needs to operate correctly without making the motor a pooch in the bottom and mid-range. Since Comp says this is the largest cam you can use with a stock converter, I suspect that you're going to try it with a stock converter and that will just make things worse. I have an idea that you will still not understand this, so you will just have to experience what we're trying to tell you and go from there.
 

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The 270h has an RPM range 1500-5800 which is also nearly identical to the intake manifold.
Richard/Tech is correct again... we're talking from experience... that's why you asked in here... don't expect much from the 500 - 2500 RPMs part of that 1500 - 5800 supposed power band with a 224/224 cam... or you'll be in the same boat as this guy:

http://www.hotrodders.com/forum/low-power-fresh-468-chevy-424834-18.html

http://www.hotrodders.com/forum/low-power-468-cam-swap-430905.html
.
 

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I see no problem running a "roller" cam with 220º duration and a tight ICL. When off road and in low range in the transfer case,I see that truck being a beast.If your transfer case is 1.8:1,in low range, that gives you a 7.4:1 effective rear gear ratio for off road. With 4.1:1 gears in high gear and high range I see 60 mph @2300 rpm for driving on road.. That should work fine.
 

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BK2Life,

Does your Scout have a working low range available? Do you have a complete Chevy drivetrain?
 

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Discussion Starter #12
I don't think you're understanding what we're trying to tell you here. Let's try another approach....
this is the largest cam you can use with a stock converter, I suspect that you're going to try it with a stock converter and that will just make things worse..
it’s a manual, SM465…

Richard/Tech is correct again... we're talking from experience... that's why you asked in here... don't expect much from the 500 - 2500 RPMs .
from the graphs ive seen nearly 300ftlbs/tq at 2600 is pretty decent

BK2Life, Does your Scout have a working low range available? Do you have a complete Chevy drivetrain?
yes, and yes

And thanks for the replies, for what it’s worth, this is probably the 50th engine I have assembled, ranging from stock to twin turbo’d, tunnel ramm’d to efi.. I'm no newbie, just never built a ‘low-rpm’ torquey rat.

Again thanks guys for your comments..
 

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from the graphs ive seen nearly 300ftlbs/tq at 2600 is pretty decent

yes, and yes
That's what we've been saying, from 2500 on up you should be making some power... peaking around 500 lb.-ft. at 4000...

Since you have a low range to use, it should be workable and enjoyable then...
 

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Your intake leans your choices toward the 268H or 270H (honestly not much to choose there), I would even lean smaller to the 262H but it sounds like your emphasis is midrange power.

You need to specify an RPM range to get an educated guess, ideally you cam for torque peak near cruise rpm hence the replies your getting regarding gearing etc. Unless your willing to change the final ratio it restricts what most here would consider ideal...in other words the most enjoyable to drive under typical driving conditions.

Your engine is close to stock except the intake and headers, I wouldn't go bigger than the 270H and would likely go with the 262H to make better use of what you have without changing everything else.
 
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