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351c 2v Cam advice
#1
Yet another cam thread.... 
351c 2v 
Edlebrock 2750 performer Intake 
Quick-fuel Slayer 600cfm vs 
Dual exhaust with stock manifolds...  might get headers later but in no rush
Screw in studs and guide plates with comp cam roller rockers 1.73 ratio.  
Sealed power HT900 lifters, with 2 days of driving on them, will replace.

So I just did all the work listed above when I put on some rebuilt heads.  Drove it for about a day and some serious noise started coming from my passenger side valve cover.  Popped it off and one cylinder 1 rocker was completely off the spring with a bent pushrod, and the other rocker was bottomed out on the stud and loose, also scored on the bottom from where its scraping the pedestal. A shop recently replaced my lifters and I'm thinking the new lifters ground down some already unhealthy cam lobes.  Long story short new cam is the diagnosis,  will check to see the health of the lifters after I take off the intake. 

I want a good power upgrade, about as much as I can get without replace my springs or pushrods (at least immediately). I don't know my spring rate, I'm guessing its close to stock, which is? Heads are on, engine is in the car. I wan't a nice power upgrade from stock that I'll noticeably feel but is also good for city driving and road trips.  This is my daily driver. Right now I have 3.00 rear gears. I plan on getting the radical punch later with an AOD trans and 3.50-3.72 rear gears. 

Here's what I'm thinking: (edited)

1st Choice (If I can get away with not changing my springs, at least right away): Comp Cams Xtreme Energy with Duration 262/270 (218/224 @.050" lift) , Lift .513/.520, 110 lobe separation. $143

2nd Choice Summit's SUM-5200 cam with specs Duration 282/292 (201/214 @.050" lift) , Lift .486/.512, 112 lobe separation. Great reviews and only $73. Also said it works with the stock springs.

3rd Choice Comp Cam High energy 32-22-13 with Duration 268/268 (218 @.050" lift) , Lift .494/.494, 110 lobe Separation. $140

Any thoughts?  Good cam? Better ideas?

Thanks in advance.  I've learned everything I know on this car with much help from you guys. 
[Image: IMG-6482.jpg]


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#2
What is your static compression ratio? Might be worth measuring everything while you have the heads off to install screw in rocker studs.
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#3
(03-09-2019, 04:58 PM)Bentworker Wrote: What is your static  compression ratio?  Might be worth measuring everything while you have the heads off to install screw in rocker studs.

I'm not sure. I'd imagine the ratio is stock for a 1971 2v.  Also the heads are back on. Hopefully don't have to remove them again, fingers crossed and they do have screw in studs.
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#4
Got any pictures of your valvetrain setup?

You have guideplates under your studs correct?

The Summit cam you picked out seems pretty mild, low ramp rate, not a ton of lift, seems reasonable. I don’t think I would consider using a new cam with anything other than new lifters.
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#5
That should work well for you.

Never use old lifters on a new camshaft. The old lifters have developed wear patterns that won't match the surface of the new cam.

Whether or not you can reuse your pushrods depends on several factors. You said one is already bent, you'll need to check all of them for straightness. Easiest way is to roll them back and forth on window glass, see if you feel any bumping. You'll also need to verify that the length of them is compatible with your new cam, and you have the correct contact pattern between the rocker tip and the valve stem. You may need to get a pushrod length checker.



“If you can't explain it simply, you don't understand it well enough.”
--Albert Einstein
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#6
I went for a little more oomph and got a CompCams K32-421-8 kit.  Came with hydraulic lifters, lifter 'keeper,' and a timing chain/sprocket set-up, and I added some CompCams 7825-16 Hi-Energy push rods to go with the 17045-16 Hi-Energy die cast aluminum 1.73 roller rockers.  The lifter 'keeper' is necessary for the hydraulic roller lifters to maintain their alignment, and will require drilling and tapping the block in the valley.  

The cam is pretty 'middle of the road,' as in better than stock and not getting into the racing cams range.  After doing some fuzzy math using the CompCams CamQuest utility (plugging in all the other engine mods I did, including headers, intake, carb, etc.), I figure I'm in the 400-ish hp range, and the car runs great! It's backed up by an AOD and 3.00 rear gears - and has no issues with burn-outs or just putt-putting down the road.

Hope that helps!

Eric

[Image: mach1sig2.gif]
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#7
(03-09-2019, 06:42 PM)Mister 4x4 Wrote: I went for a little more oomph and got a CompCams K32-421-8 kit.  Came with hydraulic lifters, lifter 'keeper,' and a timing chain/sprocket set-up, and I added some CompCams 7825-16 Hi-Energy push rods to go with the 17045-16 Hi-Energy die cast aluminum 1.73 roller rockers.  The lifter 'keeper' is necessary for the hydraulic roller lifters to maintain their alignment, and will require drilling and tapping the block in the valley.  

The cam is pretty 'middle of the road,' as in better than stock and not getting into the racing cams range.  After doing some fuzzy math using the CompCams CamQuest utility (plugging in all the other engine mods I did, including headers, intake, carb, etc.), I figure I'm in the 400-ish hp range, and the car runs great!  It's backed up by an AOD and 3.00 rear gears - and has no issues with burn-outs or just putt-putting down the road.

Hope that helps!

Thats a little more lift than I want I think.  What do you think of the Comp Cams Xtreme 32-242-4 Duration 262/270 (218/224 @.050" lift) , Lift .513/.520, 110 lobe separation as a step under? Still trying to figure out if ill need to change springs right away.
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#8
Sorry if I missed it but did you install new hardened pushrods when you had the head work done or did you re-use the stock pushrods?

73 conv. 460, D0VE large valve heads, Performer RPM manifold, Voodoo 227/233 cam, Holley 950 HP carb, C6 trans, 3.25 trak-loc.
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#9
I think the Summit 204/214 cam would be just the ticket for your use.


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#10
(03-10-2019, 06:23 AM)TommyK Wrote: Sorry if I missed it but did you install new hardened pushrods when you had the head work done or did you re-use the stock pushrods?

I did not.  I need to.
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