So who's running a Comp XE268?!

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read all the posts again and see if a cam with that timing is right for U and your build
if timing is just right a voodoo will make more power
If you do not appreciate the low speed problems some experience then go smaller on the duration
or if you are not into converters and gears
you can get the same power lift below the curve with a MOPAR cam from Voodoo, Howard, Bullet, Hughes, Engle etc
unfortunately comp does not make an XE-HL shorter than 274
so how do you drive
is mileage important etc
do you like slipping the clutch
great cam for a chevy
 
@AJ/FormS
Nice book.
To make max power, a 750 or bigger will be needed.
A smaller 650/600 will be super streetable.

Builders choice.

@Wyrmrider

I initially went with the Lunati version only to have them send me the wrong cam and initially refuse to exchange the still brand new cam out for the correct one with a fuel pump provision.

It took over 3 weeks and so one call to a lawyer to get my money back. Lunati has no care or concern that they screwed up. No care or concern from myself build or time frame. I was outright told so on the phone.
 
The XE268 is a good all around hot street hyd cam for a SB if you have the rest of the parts necessary to allow it to work properly in your combo.
Enough compression, stall, gear, carb, exhaust, ign tuning..... and it’s a nice little cam.

Will it be “optimum” for every combination? No.

But as long as your build has the ingredients to allow that cam to work, the motor will run well and make good power.

As always, a little common sense goes a long way.

If someone is having success with that cam in their 8.5cr 408 with a stock converter and 2.94 gears in a Dart........ that doesn’t mean you’ll have the same experience in your 100K mile 8:1 318, dual exhaust with logs, with the stock trans/lock-up converter and 2.45’s in a Fifth Ave.

The smaller motor will need the rest of the combo to be closer to optimum in order to get truly satisfying results.
For a 318, I’d be looking for something more like a true 9-9.5:1, 2800+ stall, 3.55’s+, headers, recurved dist, maybe a little head work, etc.
 
Put on in my 360 with a 4 speed, damn **** runs like a bat out of hell. If you put it in a auto use some stall 3.55 if your CR is lower than 9:1
 
360 w/ J heads, xe268h, LD340, 750DP, 2500 converter, 2.94 gears and a bad tune for altitude ran 105+ at vegas. It was in a 3300+ pound demon with a part throttle launch, 2.15 60'.

The thing got 20mpg at 60mph on the highway too.

It's a pretty docile cam in anything larger than a 340. Time it with about 16-18 initial and it will run well right off the bottom.
 
What would be a good converter to run with it if i was to get my hands on some 3.55 gears for the rear? I plan on going rear end hunting a little more once engine is built, also AJ i decided to have my machinist deck it to 9.59 to square it up and give me better quench. I already have my holley 650 double pumper vacuum secondarys ready to go hope that carb will be enough i didnt really want to go with 750, it is a 90% street car. Im all about the torque
 
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There is no 650 double pump, vac secondary. It's a double pumper or vac secondary. It might be a dual feed on the vac sec.

Buy a good converter is my only suggestion. The car I mentioned had a shelf 2500 hughes converter in a 904 trans. If the car had a better converter, it would have MPH faster is my guess.
 
crackedback said:
There is no 650 double pump, vac secondary. It's a double pumper or vac secondary. It might be a dual feed on the vac sec.

Buy a good converter is my only suggestion. The car I mentioned had a shelf 2500 hughes converter in a 904 trans. If the car had a better converter, it would have MPH faster is my guess.
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Oh alright yeah my fault its a dual feed vacuum secondarys
 
That's the model number. Look on the choke horn for a list number.

listnumberlocation.jpg
 
As I said earlier, in the wife’s ride, 360/@04/3.55’s on 26x10x15, we went with a 2400 stall. I would not go tighter than that.
 
rumblefish360 said:
As I said earlier, in the wife’s ride, 360/@04/3.55’s on 26x10x15, we went with a 2400 stall. I would not go tighter than that.
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Do you think ill run into issues with dual feed 650cfm vac 2ndarys? Worried the cam to big for the carb, also i do plan on doing more stall around the same
 
No. I Initially started and ran the car for a season with a 600 Edelbrock AFB carburetor. No issues whatsoever. Plenty of CFM for the street. I had the car WELL over 100mph.
 
Oh, cam size does NOT dictate carb size. What does is the combination of the engines intended purpose/useage and the ability (how much or little) of the engine to pump air in and out along with the intended forecasted power output and engine size.

A good example is the early 440’s in the big Chrysler cruiser cars and Hwy. gears.
They used a 600 AFB.
The HP 440’s in there high performance cars like the Road Runner and Chargers etc.... used a 750.

A big swing in cfm. And there not track cars. Just high performance street cars.

Then there is the monkey wrench in the works. Restrictor plate engines. There limited to a certain size carb. Class dependent, but you will often see a 390 cfm carb demanded. and they lunch out some big power with a slew of limitations.
 
op did you say what heads??
"give me better quench"
thanks for the info rumble
nothing but shelf cams from Lunati
 
The carb will be OK. Not my preferred deal, it will work with some tuning after you get it on the engine.

Converters are the SINGLE most important piece of the puzzle in an automatic car. With converters, you want as much flash as you can stand and still have it tight when cruising. It's not hard for a good converter shop to build something like that. It will cost more than the shelf stuff, but the slip at cruise will be much less. That equates to better fuel economy. A good one is a huge benefit all around.
 
Yeah hope the carb will work out with this build and hope the vacuum secondarys wont give me trouble. The converter i was going to use was in a A904 that was behind a 69 2 barrel 318, so i will probably have to get a new one. The guy i bought it off of said it was rebuily and looks fairly good but i dont know the size on the converter, ill have to pop it out when i get home. Betting no matter what ill need a new converter for proper stall
 
I just got my 68 Dart 340 Ragtop on the road and not happy with the performance. Cam unknown but thought to be stock 68 340 4spd cam.(should have changed it) Stock freshened bottom end. Motor 20 over KB hypers, around 10:5 to 1 160 PSI cranking compression. Eddy closed chamber,Eddy 600 carb, stock manifolds,4 speed 323 rear ,2" exhaust. 15" rear tire 14" front. Motor ran better when tired. No A/F gauge but have to keep half choked till warm. Would New Eddy heads from stock X heads make that much difference with Carb ? Thinking maybe this cam could help and maybe see better mileage. I know Cam tech. has come a long way. Street cruiser no track.
Don't want to give up on it yet will maybe try re-jetting but not too familiar with Eddy carbs .I saw this thread and figured I'd throw it out there in case I do change it.
I try and do everything myself so yes I stumble along the way.
 
Kendog 170 said:
I just got my 68 Dart 340 Ragtop on the road and not happy with the performance. Cam unknown but thought to be stock 68 340 4spd cam.(should have changed it) Stock freshened bottom end. Motor 20 over KB hypers, around 10:5 to 1 160 PSI cranking compression. Eddy closed chamber,Eddy 600 carb, stock manifolds,4 speed 323 rear ,2" exhaust. 15" rear tire 14" front. Motor ran better when tired. No A/F gauge but have to keep half choked till warm. Would New Eddy heads from stock X heads make that much difference with Carb ? Thinking maybe this cam could help and maybe see better mileage. I know Cam tech. has come a long way. Street cruiser no track.
Don't want to give up on it yet will maybe try re-jetting but not too familiar with Eddy carbs .I saw this thread and figured I'd throw it out there in case I do change it.
I try and do everything myself so yes I stumble along the way.
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That should run pretty good. Jet up or bigger carb and headers and 2 1/2" exhaust with a x pipe would be good. Tall tires is probably hurting your 3:23's. A 3:55 or 3:73 gear would help.
 
Kendog 170 said:
I just got my 68 Dart 340 Ragtop on the road and not happy with the performance. Cam unknown but thought to be stock 68 340 4spd cam.(should have changed it) Stock freshened bottom end. Motor 20 over KB hypers, around 10:5 to 1 160 PSI cranking compression. Eddy closed chamber,Eddy 600 carb, stock manifolds,4 speed 323 rear ,2" exhaust. 15" rear tire 14" front. Motor ran better when tired. No A/F gauge but have to keep half choked till warm. Would New Eddy heads from stock X heads make that much difference with Carb ? Thinking maybe this cam could help and maybe see better mileage. I know Cam tech. has come a long way. Street cruiser no track.
Don't want to give up on it yet will maybe try re-jetting but not too familiar with Eddy carbs .I saw this thread and figured I'd throw it out there in case I do change it.
I try and do everything myself so yes I stumble along the way.
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Agree with the others, work on tuning it and start a thread.
A tall rear tire diameter (rolling radius) could be working against engine response, not the wheel diameter. But regardless, try tuning it.
Start with ignition timing, and then go over the carb. Low rpm,and cruising is not the jets, it will be the throttle position, idle mix screws, fuel level and rods/jet combo.
Work on idle and then cruise. Then full power and pump shots. its iterative. There will be steps forward and back.
 
ir3333 said:
your car should run hard as is.Something is not right?
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I agree . I'm scrambling right now as I sold my house and have 2 weeks to get out. When things settle down I will start a thread. No garage for a long while.Really gonna miss it. Couple of pics of car my friend took on Instagram.

Dart Pic 1.jpeg


Dart Pic 2.jpeg


Shop.jpeg
 
you sold that???
agree with Ir something's not right
AJ take a look at his combo
exhaust etc do not make your problem
unknown cam might
as said start with advance curve and tune
 
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