Fastest time with a 268dur cam?!

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vntned

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Like it says, curious to how fast some of y'all have managed to go on a mild 268 duration cam. Wether it's the 268H, 268AH-10, XE268H from Comp, or any similar grind from any of the other manufacturers.

If possible please give complete engine specs!
 
Just mentioning a 268 cam will make me puke in less than 4 seconds flat....call a cam grinder and get a better grind or dont worry about 1/4 times. Guessing you would be lucky to break into 14's if that
 
magnummopar said:
Just mentioning a 268 cam will make me puke in less than 4 seconds flat....call a cam grinder and get a better grind or dont worry about 1/4 times. Guessing you would be lucky to break into 14's if that
Click to expand...
Wow,interesting comment...Had several 360 LA combinations,I have been involved with: mild stall(24_2800 converter,3:55 to 4:10 gears,mild ported J castings,1:88\1.60 GOOD VALVE JOB..., Some with the 9.0 to 1 Speed Pro hypereutectic pistons,some with stock 70's 360 slugs,re ringed.... 5 different combos,all a bodies.. Once tuned,all run 13.20's,- 12.60's.. A simple mild Crower 31916 ,the whole time.. (when you know an engine builders history,It sure helps a lot...)
 
My friend has the Comp Cam 268 in his "smog 318 motor" with a set of 1.88/1.60 heads has gone a best of 13.75 usually runs in the 13.85-13.95 area..of coarse the 3.91 gears help a lot..
 
268 advertised duration on a cam means nothing. You could have 20 different cams, all with 268 advertised duration, and all of them could have different durations at .050.

Advertised duration is useless.

Comp cams 268 for a SB mopar is 224/[email protected], .477/.480 , 110lsa.
 
The reason so many people run a "268" is because its universal, as in it works over a wide variety of combos from low comp smog head, stock converter to 10-1 , good heads and 2400 converter...it just doesnt do any of it very well. You will be leaving horse power on the table if you use one.
If you call a good cam grinder with all your info, like Racer Brown, he can grind a cam for you that will out perform a "268" by a bunch, you will be happy you did and you will be faster than all the other "268" guys. Its a GM design from the 70's and you wouldnt listen to an 8 track instead of an MP3 would you? Do your engine a favor and get a custom cam ground to your exact combo.
 
roccodart440 said:
268 advertised duration on a cam means nothing. You could have 20 different cams, all with 268 advertised duration, and all of them could have different durations at .050.

Advertised duration is useless.

Comp cams 268 for a SB mopar is 224/[email protected], .477/.480 , 110lsa.
Click to expand...
Had a comp cams 268 in otherwise stock 70 340 in my 65 cuda. 3.55 rear, 904 with 2400 stall.
Best 1/8 mile time 9.02( low 14s)
Changed to lunati voodoo cam with rhoads lifters and new timing chain.
With no other changes ran consistant 8.5s with a best of 8.34 ( low 13s )that promply toasted my trans. on that pass. lol.
 
So I just got off the phone with the guy at Racer Brown. I talked with him for a solid 23minutes, and he could've charged me a dollar a minute and I would've paid! The guy is very knowledgeable and was super helpful!

After giving him all the specs on my build, and my intentions of primary use of the car, these were his general recomondations:

110LSA
220ish duration @0.050"
450ish lift
Non split duration

That info ironically corresponds quite well with the Comp 268H. It's specs are as follows:

110LsA
218 dur @0.050"
454 lift


LOL!!!
 
vntned said:
So I just got off the phone with the guy at Racer Brown. I talked with him for a solid 23minutes, and he could've charged me a dollar a minute and I would've paid! The guy is very knowledgeable and was super helpful!

After giving him all the specs on my build, and my intentions of primary use of the car, these were his general recomondations:

110LSA
220ish duration @0.050"
450ish lift
Non split duration

That info ironically corresponds quite well with the Comp 268H. It's specs are as follows:

110LsA
218 dur @0.050"
454 lift


LOL!!!
Click to expand...

The last hydraulic cam I tried in this range was a Howards 267 cam, it ran great. I'm probably going to be using it again.

108 Lsa
267 advertised
220 at .050"
.506 lift
 
stock 340 cam=268/276, .430"/.444", in a 4 speed Duster 340, all stock except-750 avs, LD340 intake, headers, slicks, 2.5" mufflers, superstock springs, 4.56 gears=12.9 seconds @ 108 mph
 
Marcohotrod said:
stock 340 cam=268/276, .430"/.444", in a 4 speed Duster 340, all stock except-750 avs, LD340 intake, headers, slicks, 2.5" mufflers, superstock springs, 4.56 gears=12.9 seconds @ 108 mph
Click to expand...

And that has [email protected] for duration. Way bigger than the comp cam 268

This is why we NEVER use advertised duration numbers to compare cams.
 
roccodart440 said:
And that has [email protected] for duration. Way bigger than the comp cam 268

This is why we NEVER use advertised duration numbers to compare cams.
Click to expand...

That cam you're specing numbers from is the P4452761 cam and I think the '68 only stick cam. The run of the mill 340 cam only has 208/214 @.050" for duration I believe.
 
vntned said:
So I just got off the phone with the guy at Racer Brown. I talked with him for a solid 23minutes, and he could've charged me a dollar a minute and I would've paid! The guy is very knowledgeable and was super helpful!

After giving him all the specs on my build, and my intentions of primary use of the car, these were his general recomondations:

110LSA
220ish duration @0.050"
450ish lift
Non split duration

That info ironically corresponds quite well with the Comp 268H. It's specs are as follows:

110LsA
218 dur @0.050"
454 lift


LOL!!!
Click to expand...

Its not ironic, its the correct cam for that exact combo, however if you call most of the box guys hot line you will find that they recommend that cam about 80% of the time regardless of what your combo is.

T-N-T said:
The last hydraulic cam I tried in this range was a Howards 267 cam, it ran great. I'm probably going to be using it again.

108 Lsa
267 advertised
220 at .050"
.506 lift
Click to expand...
In my opinion, this is a vastly better grind but would require a bit more compression and better than 1.88 intake to take full advantage.
 
Essentially we are talking about cams in the [email protected] range and .450 to .500 lift that have a relatively mild idle.

Here would be my bumpstick of choice in the 268 realm: Crane 693801
222/[email protected]
.467/.494 lift
114LSA
Hyraulic Flat Tappet
 
T-N-T said:
The last hydraulic cam I tried in this range was a Howards 267 cam, it ran great. I'm probably going to be using it again.

108 Lsa
267 advertised
220 at .050"
.506 lift
Click to expand...
Running a Howards LA hydraulic roller in my Magnum,great cam
 
Marcohotrod said:
stock 340 cam=268/276, .430"/.444", in a 4 speed Duster 340, all stock except-750 avs, LD340 intake, headers, slicks, 2.5" mufflers, superstock springs, 4.56 gears=12.9 seconds @ 108 mph
Click to expand...

Bingo!... and with 3.23's this would usually give a smooth idle and 20 + mpg.
pretty hard to beat the factory piece for an all round street car
 
Last edited:
ir3333 said:
Bingo!... and with 3.23's this would usually give a smooth idle and 20 + mpg.
pretty hard to beat the factory piece for an all round street car
Click to expand...

Been sayin that ever since I joined here. Been argued with ever since.
 
Back in 1989 I stuck a Crane 693511 and matching springs in an otherwise bone stock '68 340 long block with cheapie headers and a '71 Thermoquad intake and carb, and a 175hp nitrous plate. Specs: intake 212° @ .050, 268° .459; exhaust 220° @ .050, 276 ° .480; 112LSA
That went into my '74 Barracuda with a 4sp. Car had 3.23s, and a 4spd. I drove it daily, and at the time in CT it needed to pass the idle emissions test. I never checked mileage but it did pass the test easy enough. That car went 13.20s with me rowing it, and with the nitrous plate 12.70s. It was about 3500lbs with me in it. They make plenty of steam if the combo is right.
 
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