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I invent stupid usernames
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Discussion Starter #1
This summer I'll be converting my small block chevy to a roller cam like I decided in a previous thread http://www.hotrodders.com/forum/roller-rockers-need-guide-plates-495026.html.

I was recommended the XR270HR by Comp Cams, and by Lunati I was recommended the VooDoo 20120710

XR270HR (12-422-8) specs
218/224 @.050"
270/276 adv. dur.
.495/.502" lift w/ 1.5 rockers

VooDoo specs
211/219 @.050"
262/270 adv. dur.
.507/.515" lift w/ 1.5 rockers

Truck weighs 4,600 pounds and is 2wd

3.07 rear gear, possible change to 3.42 so I want a cam that will work well with both

9.3:1 compression

Summit 152123 heads (improved camelhump/fuelie repro heads)

hooker headers and dual exhaust

Edelbrock dual plane intake with 600 cfm carb

I want to use this for "truck stuff" like it was built for, but I also want to be able to put my foot to the floor and feel it. Current cam is a comp XS256S
 

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Personally, the VOODOO is a more modern lobe profile than the Comp. I suspect this would get you a little more 'area under the curve'. Harold Brookshire really outdid himself with the first voodoo designs.
Don't overlook Bullet, Howards and Erson (PBM) for bigger companies. Theres also Mike Jones and Chris Straub at the boutique level.
 

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I invent stupid usernames
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Discussion Starter #3
subscribing.
Personally, the VOODOO is a more modern lobe profile than the Comp. I suspect this would get you a little more 'area under the curve'. Harold Brookshire really outdid himself with the first voodoo designs.
Don't overlook Bullet, Howards and Erson (PBM) for bigger companies. Theres also Mike Jones and Chris Straub at the boutique level.
I was considering Erson and Crower as well
 

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I invent stupid usernames
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Discussion Starter #5
I forgot to put this in the original post, but how would I go about retro fitting a roller cam into a non roller block? What would I all need parts-wise, and what would I have to modify or watch out for?
 

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I forgot to put this in the original post, but how would I go about retro fitting a roller cam into a non roller block? What would I all need parts-wise, and what would I have to modify or watch out for?
You would use a retro-fit style cam, not a stock OEM type roller cam, as the nose end is different, .The rest is pretty easy, you need a cam button to prevent cam forward and aft motion in the block, a good solid timing chain cover so the thrust from the button doesn't flex the cover and give too much clearance, and a set of link bar retro-fit roller lifters.

This keeps the timing chain the same as stock. I would recommend a cast aluminum timing cover rather than some thin stamped steel version, or stamped aluminum, You can find them around the web for around $30.

Pushrods will be different, the roller pushrods are a bunch shorter, like .600" or more shorter.

Valvespring may be different, depending on what you have now.
 

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I invent stupid usernames
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Discussion Starter #7 (Edited)
You would use a retro-fit style cam, not a stock OEM type roller cam, as the nose end is different, .The rest is pretty easy, you need a cam button to prevent cam forward and aft motion in the block, a good solid timing chain cover so the thrust from the button doesn't flex the cover and give too much clearance, and a set of link bar retro-fit roller lifters.

This keeps the timing chain the same as stock. I would recommend a cast aluminum timing cover rather than some thin stamped steel version, or stamped aluminum, You can find them around the web for around $30.

Pushrods will be different, the roller pushrods are a bunch shorter, like .600" or more shorter.

Valvespring may be different, depending on what you have now.
I'm leaning toward the cam that comp recommended as it has slightly less lift and isn't butting against the max lift for my heads (.520") I have a PBM Erson double roller timing set right now, would this work with an aftermarket roller cam and a cam button? The current valve springs are comp pn. 981-16 and the recommended springs for this cam are 986-16. Should I maybe go one step down in size on the Extreme Energy line, the 270HR seems a little big for what I need, but the current cam has the same @.050 specs, just in solid flat tappet form.
 

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I'm leaning toward the cam that comp recommended as it has slightly less lift and isn't butting against the max lift for my heads (.520") I have a PBM Erson double roller timing set right now, would this work with an aftermarket roller cam and a cam button? The current valve springs are comp pn. 981-16 and the recommended springs for this cam are 986-16. Should I maybe go one step down in size on the Extreme Energy line, the 270HR seems a little big for what I need, but the current cam has the same @.050 specs, just in solid flat tappet form.
Pick a cam that runs in the rpm range that you intend to run. Truck with 3.07 gears with a stock converter on 33ish" tires is not going to receive the same cam recommendation as 2500-3000 stall with 4.10's.

I'd strongly recommend nailing down what you intend to do behind the motor before picking a cam. And you need to pick the correct springs. Rollers require a much stronger spring inorder to maintain just about any valve control over 4500-5000 rpms due to added weight of the roller lifter and more aggressive cam profile that a roller lifter can handle. Springs are darn cheap in the list of items needed for this swap - they are not an item to cheap out on. There are many sources other than Comp Cam for springs as well. A set of beehives will allow for more lift, safely, also.
 

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Pick a cam that runs in the rpm range that you intend to run. Truck with 3.07 gears with a stock converter on 33ish" tires is not going to receive the same cam recommendation as 2500-3000 stall with 4.10's.
Well said. Sounds to me that you need to choose a cam that works well from 1500-4500 RPM. And head flow characteristics are key. Did the Comp Cams guy even ask you about intended RPM range or head flow specs? That's certainly what Mike Jones at Jones Cam Designs would do.

And make that intake manifold a high rise, like Performer RPM or Weiand Speed Warrior. Doug Flynn at Holley says on a 350-406 they give up virtually nothing at very low RPMs compared to a low rise manifold, but they make more power everywhere else.
 

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You will be able to re-use your current timing set. I'd recommend a lock plate, it makes it easier to keep the button in place during installation.
 

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I invent stupid usernames
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Discussion Starter #11
Well said. Sounds to me that you need to choose a cam that works well from 1500-4500 RPM. And head flow characteristics are key. Did the Comp Cams guy even ask you about intended RPM range or head flow specs? That's certainly what Mike Jones at Jones Cam Designs would do.

And make that intake manifold a high rise, like Performer RPM or Weiand Speed Warrior. Doug Flynn at Holley says on a 350-406 they give up virtually nothing at very low RPMs compared to a low rise manifold, but they make more power everywhere else.
I'm thinking of using the Comp Cams XR258HR or XR264HR because the XR270HR seems too large for what I want. I do want some punch on the upper end, but what really matters is lower end so I'm leaning more toward the 264 especially with the probable change of rear gears. I don't want to change any more on the engine than I have to so all of what I have is staying except what I need to change to accept the roller cam.
 

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I'm thinking of using the Comp Cams XR258HR or XR264HR because the XR270HR seems too large for what I want. I do want some punch on the upper end, but what really matters is lower end so I'm leaning more toward the 264 especially with the probable change of rear gears. I don't want to change any more on the engine than I have to so all of what I have is staying except what I need to change to accept the roller cam.
Change gears first. Get into the cruise rpm you desire and then pick a converter to work with your gears and driving habits/preferences.....and then pick a cam to maximize your previous choices.

Most folks build a motor and then try to fit it into a chassis. But I think that is a mistake, especially when they have a non-conventional build. IMHO you have a non-conventional build, so I'd say you need to get your drive train and tire size determined, and then - pick a cam to operate in the window that you want it to run in.


My two cents - with them and another $2.05 you can get a coffee at Dunkin' Donuts :)
 

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For what retrofit roller parts cost and the build intent you would be better off starting with a late model roller block and I would use the Lunati or one of Howards similar cams paired with factory roller lifter using factory spiders. You don't need a four bolt block either.

One piece main seal is a desirable feature of the roller blocks not to mention simplicity of the dogbone lifter retainers and the lower prices of the parts easily pay for another block.

Add some decent flowing aftermarket CI heads in the 165-170 cfm flow range and it will be a good truck engine...would not go bigger than 270 advertised duration and stick close to 112-114 LSA.

Gears should be closer to 3.73:1/4.11:1, short changing yourself with gearing is a mistake if you ask me...if you want mileage build a 700R4 trans to go with it.
 

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I invent stupid usernames
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Discussion Starter #14
For what retrofit roller parts cost and the build intent you would be better off starting with a late model roller block and I would use the Lunati or one of Howards similar cams paired with factory roller lifter using factory spiders. You don't need a four bolt block either.

One piece main seal is a desirable feature of the roller blocks not to mention simplicity of the dogbone lifter retainers and the lower prices of the parts easily pay for another block.

Add some decent flowing aftermarket CI heads in the 165-170 cfm flow range and it will be a good truck engine...would not go bigger than 270 advertised duration and stick close to 112-114 LSA.

Gears should be closer to 3.73:1/4.11:1, short changing yourself with gearing is a mistake if you ask me...if you want mileage build a 700R4 trans to go with it.
I don't have the funds to change blocks because that would require machining to fit my pistons and to zero deck it, and on top of that I'd still need to buy a cam and lifters, and all the retaining hardware. Definitely don't have money to swap transmissions
 

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I doubt your cam and build change wouldn't net you more than 30 HP and the same in torque, all at slightly higher rpm.

Seems hardly worth it to me considering your budget.
 

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Discussion Starter #16
I doubt your cam and build change wouldn't net you more than 30 HP and the same in torque, all at slightly higher rpm.

Seems hardly worth it to me considering your budget.
I should have been clearer, I'm not doing this for power, I'm doing it for longevity. The solid flat tappet is going to eventually wear out. And being a solid lifter setup it's beating the valvetrain up more than a hydraulic would.
 

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What?

I put 350 000 km on a solid lifter Ford 2.8L, bore wear and rings gave out long before the cam, I was the second owner and the first one didn't do regular valve adjustments.

Why do you think this is fact?

Yearly valve adjustments is all you need to stay on top of it depending on how many miles you put on it.

Never heard this wives tale before.
 

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Discussion Starter #18
What?

I put 350 000 km on a solid lifter Ford 2.8L, bore wear and rings gave out long before the cam, I was the second owner and the first one didn't do regular valve adjustments.

Why do you think this is fact?

Yearly valve adjustments is all you need to stay on top of it depending on how many miles you put on it.

Never heard this wives tale before.
Fair enough, but I have a lifter that's wearing in a funny pattern, so this cam is going to be toast one day. I'm not trying to discredit anything you're saying, just stating my point of view also
 

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You would use a retro-fit style cam, not a stock OEM type roller cam, as the nose end is different, .The rest is pretty easy, you need a cam button to prevent cam forward and aft motion in the block, a good solid timing chain cover so the thrust from the button doesn't flex the cover and give too much clearance, and a set of link bar retro-fit roller lifters.

This keeps the timing chain the same as stock. I would recommend a cast aluminum timing cover rather than some thin stamped steel version, or stamped aluminum, You can find them around the web for around $30.

Pushrods will be different, the roller pushrods are a bunch shorter, like .600" or more shorter.

Valvespring may be different, depending on what you have now.
A steel distributor gear is necessary too.
 
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