Compu cams XE268H question

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BIG difference between a big and small block. That .170" more stroke tames the hell outta that camshaft. It also produces much more torque at a much lower RPM. That's probably a damn good combo in your car. I bet it does run good.

This reply was to trudysduster. Sorry. I thought I hit the quote thingie. I guess I did not.
 
well, now that I learned the difference, XE268 it will be. If I can get someone that will degree it in. otherwise it will just have a new set of x heads on it. Thanks for the info here.
 
trudysduster said:
well, now that I learned the difference, XE268 it will be. If I can get someone that will degree it in. otherwise it will just have a new set of x heads on it. Thanks for the info here.
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That's a good choice Bill. Why not buy a degree wheel and a bridge mount piston stop and do it yourself. You will need a dial indicator too if you don't have one.

I just bought the degree wheel and a bridge mount piston stop myself and intend to learn how to do it on my build. They weren't all that expensive, around 20 bucks or so if I recall. I got them from Summit when I ordered some other stuff.

PS: Did you catch my comment about the double roller vs. the single chain if you buy the Comp kit? Just a heads up for ya.

I know when Steve and his Dad ordered their kit and had it shipped here, that's what they did.
 
piston stop I can make. degree wheel is no problem. dial indicator is what I don't have. I priced this stuff together as a kit and it was between 75-100.00. I have a couple of friends around here who is running small blocks at the track. one is running a challenger in the 10's and one is running a dragster. I am sure they have the tools to do it. the guy running the dragster works at an engine machine shop so I can get it done. I have not messed with cams in a long time. the last time I did, it was just line the dots up and go, now there are so many variables that you have to do its confusing to me and I am too old to learn new tricks. Why don't you get another load down here and stop in and degree it for me. we can go back to cracker barrel and shoot the **** some more. LOL. and I might get a wild hair up my as* and buy one and just do that. I have been know to be un predictable in my old age.
 
Compu-Cams XE-268-H and Kit

Just put one in a 1972 'Duster 340' customer rebuild.

* 9.0-1 Compression {KB Pistons}
* Stock Exhaust w/Free Flow Mufflers
* Stock Cast Iron Intake {Gasket-Matched and Minor Runner-Port Smoothing}
* Thermo-Quad 800 CFM
* Automatic
* 2500 Stall Converter {old 'B & M Holeshot'}
* 3.55 Gears
* 15" x 28" Tall Rear Tires

'Perfect Street Cam' = Pulls strong right up thru 5800 RPM's.
'Torque Power Band' = 2800 thru 4400 RPM's
 
So I've got the 268 in my 72 Dart Custom 318. The motor was completely rebuilt and put in by the previous owner and has less than 500 miles on it. I was told its .030" over with flat top pistons(he couldn't remember the compression ratio), rebuilt J heads (couldn't remember valve size), the aforementioned Comp268H, and then was topped off with the stock 318 exhaust manifolds and stock 2bbl setup. It has true duals and has been converted to electronic ignition too. Stock a904 trans and stall, and stock open 7.25" rear with 2.73 fd. The car runs fine and sounds great, but gets really lame gas mileage for a 318! It's only getting 9-12mpgs in town and driving gingerly.

Now I've been told that that I need to put on a 600cfm 4bbl and decent intake ASAP and that it'd help economy and power. And I was also told that the problem was that the cam was way to much and that is what is killing the economy.

I've got a Eddy AirGap with an Eddy 600cfm carb laying in the shop that I intend on throwing on, but will it help economy or is the cam the culprit?
 
vntned said:
So I've got the 268 in my 72 Dart Custom 318. The motor was completely rebuilt and put in by the previous owner and has less than 500 miles on it. I was told its .030" over with flat top pistons(he couldn't remember the compression ratio), rebuilt J heads (couldn't remember valve size), the aforementioned Comp268H, and then was topped off with the stock 318 exhaust manifolds and stock 2bbl setup. It has true duals and has been converted to electronic ignition too. Stock a904 trans and stall, and stock open 7.25" rear with 2.73 fd. The car runs fine and sounds great, but gets really lame gas mileage for a 318! It's only getting 9-12mpgs in town and driving gingerly.

Now I've been told that that I need to put on a 600cfm 4bbl and decent intake ASAP and that it'd help economy and power. And I was also told that the problem was that the cam was way to much and that is what is killing the economy.

I've got a Eddy AirGap with an Eddy 600cfm carb laying in the shop that I intend on throwing on, but will it help economy or is the cam the culprit?
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Sounds like a pretty big mismatch with the 2bbl & exhaust manifolds. Your choked off coming in as well as coming out.
 
vntned said:
So I've got the 268 in my 72 Dart Custom 318. The motor was completely rebuilt and put in by the previous owner and has less than 500 miles on it. I was told its .030" over with flat top pistons(he couldn't remember the compression ratio), rebuilt J heads (couldn't remember valve size), the aforementioned Comp268H, and then was topped off with the stock 318 exhaust manifolds and stock 2bbl setup. It has true duals and has been converted to electronic ignition too. Stock a904 trans and stall, and stock open 7.25" rear with 2.73 fd. The car runs fine and sounds great, but gets really lame gas mileage for a 318! It's only getting 9-12mpgs in town and driving gingerly.

Now I've been told that that I need to put on a 600cfm 4bbl and decent intake ASAP and that it'd help economy and power. And I was also told that the problem was that the cam was way to much and that is what is killing the economy.

I've got a Eddy AirGap with an Eddy 600cfm carb laying in the shop that I intend on throwing on, but will it help economy or is the cam the culprit?
Click to expand...


I'll say that tune up is likely miles off from optimum. My friends have a 360/268H 2500 verter at 3.00 gears. It gets 20mpg on the highway and about 16 around town.

What do you have for initial timing? That's the first place to start.
 
I've got the Edelbrock 600 cfm (model 1405) on an Edelbrock Performer, with electronic ignition, MSD 6AL, Comp Cam XE268H, headers, duals.. on my 360.. timing is 35 degrees advanced at about 3000 rpm with Vac Advance disconnected.. I get about 8 mpg
I know it should be getting better than that.. I will be taking it to a dyno/tune shop soon to see what we can do
 
vntned said:
So I've got the 268 in my 72 Dart Custom 318. The motor was completely rebuilt and put in by the previous owner and has less than 500 miles on it. I was told its .030" over with flat top pistons(he couldn't remember the compression ratio), rebuilt J heads (couldn't remember valve size), the aforementioned Comp268H, and then was topped off with the stock 318 exhaust manifolds and stock 2bbl setup. It has true duals and has been converted to electronic ignition too. Stock a904 trans and stall, and stock open 7.25" rear with 2.73 fd. The car runs fine and sounds great, but gets really lame gas mileage for a 318! It's only getting 9-12mpgs in town and driving gingerly.

Now I've been told that that I need to put on a 600cfm 4bbl and decent intake ASAP and that it'd help economy and power. And I was also told that the problem was that the cam was way to much and that is what is killing the economy.

I've got a Eddy AirGap with an Eddy 600cfm carb laying in the shop that I intend on throwing on, but will it help economy or is the cam the culprit?
Click to expand...

I agree with Crackedback that the tune is probably off, in addition to the mismatched parts. The Air-gap is a real good intake but it's not going to help fuel mileage due to it's design. The air-gap raises the runners and plenum above the rest of the engine providing an air-gap (hence the name) which increases low and mid range torque, but since it runs cooler it doesn't atomize the fuel as well as a non air gap style intake and good fuel atomization is a necessity for good mpg. With so many unknown's it's kinda hard to say if the cam is too much for it but I'm sure a smaller cam will get better fuel mileage, but I have also seen engines with that cam get 20 mpg (hwy). First check the timing like CB said and do what he tells you as he knows what works best for optimum economy and power. As for the intake and carb, if fuel mileage is the main concern sell the Air-gap intake and buy a performer. The Eddy 600 should be ok for mileage when tuned right. When it comes down to it most bad mpg issues, (providing the cam, heads, compression, intake, and carb are properly matched), are resolved by proper tuning.
 
Saetun said:
I run the same cam in my 318 & Evildart runs it as well in his 340 6 pack. Nice noticeable tone & I'm very happy when is hit the loud pedal.
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I really like this cam. I did go with Engle 993 springs @ 1.800 installed height to help with valve float. I was looking to make more HP (It made 340) than it did, but the Tq (375) in the low RPM range is all in @ 2200 and stays level up to 6000. I'm also running a 2800 stall in a 727 with a 8.75 rear end and 3.23 gears.
 
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