New cam for the Commando 273

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drewmac

drewmac

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I am contemplating a cam swap on my 67 273 Commando Barracuda S. My plans are for a 625 Carter (or EFI), Performer intake, adjustable 1.6 roller tip rockers, headers, full dual exhaust with h pipe to accompany the cam change. In looking at the different cam companies Lunati sticks out to me as a good looking grind. It is thier Voodoo flat tappet 262/268 cam:

Advertised Duration (Int/Exh): 262/268
Duration @ .050 (Int/Exh): 220/226
Gross Valve Lift (Int/Exh): .475/.494
LSA/ICL: 112/108
Valve Lash (Int/Exh): Hyd/Hyd
RPM Range: 1400-5800

Has anyone used this cam in something similar? Will it "wake up" my 273 or will leaving the stock cam in place with these other mods be enough? I guess something approaching 300hp with decent low end (With a 273?) and daily drivable would be my dream.

:violent1:
 
If you have enough gear, 3.55ish, and/or a good converter, i think it would be great. Main issue, especially with 1.6 rockers, might be retainer/valve guide clearance?
 
I am sticking with the stock pistons, 3.23 gears and the 4-speed. Where should I be with the lift to keep from making a mess of the valves? I could keep the stock adjustable valvetrain to minimize that possibility. I was thinking of a mild port and possible bigger stock valves.
Honestly my main goal is to increase the efficiency of the motor without going whole hog and losing the ability to drive it around town or to a show 500+ miles away (possibly going to Reno)
 
I'm not positive on max lift with those heads, but approaching 500" lift is close to max lift. With the stock 1.5 ratio rockers i think you'd be good. with the 1.6 rockers, you may scale back to the next step down......
http://www.summitracing.com/parts/LUN-60401/.....with the 1.6 puts you just about .500". It's less duration, but with the 3.23 gear would still be a big boost in my opinion. Hope another member will chime in and confirm the lift/guide clearance.

P.S. I would add that because your original cam thoughts were hydraulic that you prefered that style cam. A small solid grind could also be a option, but that would include some periodic lash checks. Also, any guide clearance issues could be addressed if you chose to have the valve work done.
 
Too big for a stocker 273 especially with 1.6 rockers. The 273 is a small cubic inch engine. Think small. tmm
 
How about the Lunati Voodoo 256/262 cam that is one step smaller? Still hotter than the stock solid cam in it now but not over the top in my opinion. I could use the 1.6 roller tip rockers then. How about the valve springs. Would it be best to get matched ones from Lunati or are there some stock replacements I can get cheaper that will work (stock 340's). What about cup style pushrods for a hydraulic cam. Who makes them?
Abodybomber- I tried to find the thread you mentioned but could not find it. Can you post a link?
 
Your choice. If you have a 67 Commando it is a solid lifter motor. No reason to change to a hydraulic unless you don't want to mess with adjusting valves. The headers and exhaust will wake up your 273 more than anything. The 1.6 rockers might not do you much good. I ran the 1.6's on my desktop dyno and only gained 2 hp over the stock 1.5's I run a Isky e-4 cam in my 273 and for it's size it works well and you can use it with all your stock components. In fact it produces more torque than either of the Voodoo cams, the same HP as the #701 and within 7 hp. of what the #702 produces. tmm
 
I think looking for a different intake than a performer would be a good idea. Keep an eye out for a vintage Edelbrock LD4B and try a small Holley like a 600.
 
Now that the cam is broken in on dads engine, I will see if I can 'neek the keys again and get a video of it. But it doesnt have the hypo pistonis in it....
 
4spdragtop- Saw the video. Sounds great. My 67 formula S does have the hi comp pistons. You used a Comp 270 solid right? I think for now I will do headers, exhaust and the 625 carter and keep my eyes open for an intake and keep the stock cam. I will see what I get and make a cam change if it still not where I want it. Keep the vids coming.
 
Hi Drew, yes we used the solid cam 270S, the kit # with everything is CL20-246-4 . The CL stands for cam and lifters....always specify that you want a dbl roller with the kit as you will only get a single roller, Badsport a member here give me a heads up on that. If you go to youtube, I have 3 vids on there with my signon. I will try to get more before it goes for winter hibernation. Take lotsa pics/vids whichever route you decide to go. Oh ya also search for member Toolmanmike, he did a 273 up REALLY nice!
 
4spdragtop- Yes, I have seen that thread. I have gotten some good input from him on this one as well. I will keep plugging away and we will se where we get.
 
Drew, A member here has a Hughes Whiplash cam for sale here. I clicked on the Hughes link to hear what this cam sounds like in a 318. Very impressive! It idles with authority. In a 273 it would be half again as rough idling. I put the specs in the dyno program and it is almost the same as the Isky E-4 but the isky idles with just a little chop. If I had louder exhaust and headers, mine would sound more powerful. I don't think you need a cam with .500 lift in a 273, for it to be fun to drive. I don't say this often but 273's do have their limits. You already have the good 273, I would put some headers and good exhaust on and see what it runs like. After those additions you may want to tune your carb to make it run even better. Then if you find a cam you want to try go for it. But don't go too big. As I have illustrated earlier, you don't need a big cam to make the 273 run good. tmm

http://www.hughesengines.com/Index/...V2hpcGxhc2ggTXVzY2xlIENhciBDYW1z&partid=25113
 
Toolmanmike- Thanks for the info. I do agree with you. From what I have seen in other threads and from your experiance if I do anything it will be the Isky-E4 or something very close. I will work on freeing up the exhaust, intake and heads first. Kudos to all who chimed in on this thread!
 
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