Comp Cams Xtreme Energy 268 ?s

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DartGTDan

DartGTDan

'71 Dart GT Fan
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My engine builder has offered me the above mentioned cam (& matching bore lifters) that was removed from a '65 Cuda with a 273. He told me the cam wouldn't allow the Cuda's power brakes to work properly, so it was removed after about 200 miles.

My 120,000 mile engine is getting a basic stock rebuild with a .030 overbore. It does/will have an Edelbrock LD4B intake & 1406 carburetor, double roller timing chain/gears, MP electronic ignition, factory exhaust manifolds with FlowMaster 40s and 2 1/4" pipes, factory heads (with hardened valve seats), A904 transmission (stock convertor), and the factory 3.23:1 sure-grip 8 3/4" rear-end, with P245-60R15 tires.

I'm "camshaft dumb", so I'm looking to the FABO experts for guidance. Is this cam to much for my ice cream parlor cruiser? I love the sound of a lumpy cam, but I don't want to lose the reliability/drivability of a stock motor. I also don't want to have to "need" headers or a higher stall torque convertor, etc...

What do you say?
 
Don't use that cam in a 273. It is a nice cam for a 340, borderline too big for a stock 318 with factory convertor and rear gears and too big period for a 273. Oh there will be a coupe guys that say it works or is perfect but how many extra parts are you going to need to make it work.
 
So you have a 318? You want at least 9.5 static compression ratio and at least a 2300 RPM converter. If you plan to use factory style pistons and a stock converter, you'll find that cam a bit "soggy" down low on the street.
 
That's a pretty good size cam for a 273. I'd be more concerned about whether the lifters were kept in order. That said, there are much better choices. Plus, your 273, if a 65 model should be a solid lifter lifter engine. You would need different pushrods to go to the 268 anyway.
 
Also, your engine should have adjustable rocker arms since it's a 65 and should have solid lifters. Those rocker arms are pretty sought after. I would make sure they are still there after the rebuild.
 
Cam came out of a 273. No mention if the engine it's going in. A 318 would need plenty of initial timing for it to work.

71 Dart GT wouldn't have a 273 unless someone swapped it out.
 
Since we haven’t heard from OP, let’s back up and see if we can connect the dots…
OP said this cam/lifters came out of a ‘65 273 that wouldn’t support it, not what it’s going in, and if it’s going in the ‘71 dart with 120k in his avatar I’d be surprised if its a 273. More likely it’s a 318-360 that may or may not have power brakes to support. I’ve got the same cam in my mostly stock 340 without power brakes but even so, it’s pulling enough vacuum to cover them. Long/Short is we need more input.
 
Sorry for the confusion!

My '71 Dart GT's engine is the original 120,000 mile 318. It is currently in the shop, for what I was thinking was, a stock rebuild. The engine builder offered me the cam/lifters that came out of a 273.

PS my car has manual brakes (SSBC front disc & factory rear drum)
 
DartGTDan said:
Sorry for the confusion!

My '71 Dart GT's engine is the original 120,000 mile 318. It is currently in the shop, for what I was thinking was, a stock rebuild. The engine builder offered me the cam/lifters that came out of a 273.
Click to expand...
Still wouldn't do it unless you are willing to jump up to a higher stall converter and a 3.55 rear gear or more. The stock 318 manifolds are quite restrictive as well. Put it in with out the right goodies to make it work and you might be disappointed.
 
Topless69 said:
Power brakes? A/C? Torque converter?
What’s the rest of the story?
Click to expand...

My 120,000 mile engine is getting a basic stock rebuild with a .030 overbore. It does/will have an Edelbrock LD4B intake & 1406 carburetor, double roller timing chain/gears, MP electronic ignition, factory exhaust manifolds with FlowMaster 40s and 2 1/4" pipes, factory heads (with hardened valve seats), A904 transmission (stock convertor), and the factory 3.23:1 sure-grip 8 3/4" rear-end, with P245-60R15 tires. Manual brakes (SSBC front disc, factory rear drum).
 
DartGTDan said:
My 120,000 mile engine is getting a basic stock rebuild with a .030 overbore. It does/will have an Edelbrock LD4B intake & 1406 carburetor, double roller timing chain/gears, MP electronic ignition, factory exhaust manifolds with FlowMaster 40s and 2 1/4" pipes, factory heads (with hardened valve seats), A904 transmission (stock convertor), and the factory 3.23:1 sure-grip 8 3/4" rear-end, with P245-60R15 tires. Manual brakes (SSBC front disc, factory rear drum).
Click to expand...
I’d follow Toolmanmike’s advice on this if you’re staying stock. You might consider buying the cam and lifters from your mechanic if you plan on upgrading later.
 
I've ran it in a basically stock 318 ( performer RPM intake, 600 slayer carb and a /6 converter) it does okay but the car isn't anything to write home about. Comp recommended it when the car still had power brakes, stock converter and a trash rear gear ratio (2.45). As stated though, there are better options out there.
 
With what you got gear stall exhaust etc.. and if you want to stick with comp cams xtreme energy line I'd be looking more at the 250 or max 256 one's or similar from other companies.
 
I agree with the advise on the 268. Too much for what you're doing.

However, since you've got it opened up, why not go with a nice 204/208 @.050 grind with 430/440" lift or so. It would run like a stocker and give you a nice boost with the intake & carb.
 
DartGTDan said:
My '71 Dart GT's engine is the original 120,000 mile 318. It is currently in the shop, for what I was thinking was, a stock rebuild. The engine builder offered me the cam/lifters that came out of a 273.
Click to expand...
Will also need the pushrods and rocker set.

from Factory V-8 Engine and Cam Specs by Year 1965-1975
All Chrysler degrees so they are comparible to each other.
upload_2022-3-10_19-26-0.png

Keep in mind the mechanical valve lash when comparing with the hydraulic
 
273 said:
With what you got gear stall exhaust etc.. and if you want to stick with comp cams xtreme energy line I'd be looking more at the 250 or max 256 one's or similar from other companies.
Click to expand...
I ran a comp XE250H in a 318 with some ported closed chamber truck heads, headers & twin 2.25" exhaust, weiand action plus and a 625 Carter Afb. Stock convertor, 3.23 gears, it was a nice little motor for crusing around.
Not fast but a reasonable bump up from stock.
 
I am running a Comp CRS 268H-10 Part # 20-212-2 in a 1970 318, factory heads,stock pistons now.
Performer 318/360 with a 600 Edelbrock and headers.Stock 904 converter 4.10 gears.
In a 63 Belvedere street car.
To me it's a pretty mild cam and is working well in this combo.
Video is pretty crappy ,not good with this stuff.
 
DartGTDan said:
My engine builder has offered me the above mentioned cam (& matching bore lifters) that was removed from a '65 Cuda with a 273. He told me the cam wouldn't allow the Cuda's power brakes to work properly, so it was removed after about 200 miles.

My 120,000 mile engine is getting a basic stock rebuild with a .030 overbore. It does/will have an Edelbrock LD4B intake & 1406 carburetor, double roller timing chain/gears, MP electronic ignition, factory exhaust manifolds with FlowMaster 40s and 2 1/4" pipes, factory heads (with hardened valve seats), A904 transmission (stock convertor), and the factory 3.23:1 sure-grip 8 3/4" rear-end, with P245-60R15 tires.

I'm "camshaft dumb", so I'm looking to the FABO experts for guidance. Is this cam to much for my ice cream parlor cruiser? I love the sound of a lumpy cam, but I don't want to lose the reliability/drivability of a stock motor. I also don't want to have to "need" headers or a higher stall torque convertor, etc...

What do you say?
Click to expand...
What cam number are we talking about there? Comp has numerous High Energy and Extreme Energy cams that fit in the "268" arena. Apples to oranges. There are a ton of 318 cam threads here on FABO. The consensus is to call a cam company with tour combination specs and they can recommend a cam or grind you one.
 
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For example: 268 high energy #CRS268-H10 218/218 268/268 .454/.454 110°
268 Extreme energy # CL20-223-3 224/230 268/280 .477/.480 110°
 
toolmanmike said:
For example: 268 high energy #CRS268-H10 218/218 268/268 .454/.454 110°
268 Extreme energy # CL20-223-3 224/230 268/280 .477/.480 110°
Click to expand...

Yes Mike, I saw the multiple 268 choices. The only info I got from my builder, is "Comp Cams X-treme Energy 268 Hydraulic". It's not enough information for me (I'm cam "dumb") to say yes to using it. From all the info posted here, I'd have to make other upgrades/changes (headers, torque convertor, etc...) to the car to make that cam work. I'm just looking for a simple/stock/reliable rebuild of the 318.
 
DartGTDan said:
Yes Mike, I saw the multiple 268 choices. The only info I got from my builder, is "Comp Cams X-treme Energy 268 Hydraulic". It's not enough information for me (I'm cam "dumb") to say yes to using it. From all the info posted here, I'd have to make other upgrades/changes (headers, torque convertor, etc...) to the car to make that cam work. I'm just looking for a simple/stock/reliable rebuild of the 318.
Click to expand...
There's tons of 318 cam threads here. There's info on a few cams that are specifically ground for a 318 with a 4 barrel and dual exhaust. I just looked through my bookmarks and couldn't find the thread. Sorry.
 
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