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73-87 Chevy _ GMC Trucks => Performance => Topic started by: dumbucket1 on July 05, 2008, 12:03:32 pm
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do I need to change the valve springs to run this cam? also whats the difference between a xe268 and xe268h? thanks
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do I need to change the valve springs to run this cam? also whats the difference between a xe268 and xe268h? thanks
Yes, you will need new valve springs
Comp makes two XE268H cams for the sbc
12-242-2 for carbs
12-268-4 for injected engines
"H" means hydraulic lifter
"S" means solid lifter
got a part # for the XE268?
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I haven't purchased it yet. It was recommended to me for an engine Im going to build ;)
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The xe250 makes better torque and is more "truck" friendly if you do any towing
The xe268 works great with steeper gears and a loose converter
with fuel headed to $5 or $6 a gallon the xe250 makes better sense
but it's your wallet......
Take a look at these dyno sheets
http://www.compcams.com/technical/DynoSheets/
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actually Im building the motor for a 1979 malibu. It will be used for mostly weekend warrior use. Mostly cruising, maybe a little quarter mile action.
The engine is going to have 97 vortec heads, stock bottom end, probably a dual plane intake, and not sure what Im going to use for a carb yet. The transmission is a 200-4r, may go with a 2500-3000 stall convertor, the rear end is a 3.73, 7.5 posi rear from a 87 monte ss
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I have an XE268 (the Xtreme Energy) in my 350 that I had put in just in May, along with a set of Dart Iron Eagle 165 heads that spec out close to Vortecs. My 12 bolt has 2.76 gears in it so not all that great with that cam, but I have a 3.40 posi waiting to get put in it. That cam should work great in your lighter and deeper-geared Malibu. I like the idle in mine. In Park it idles with some chop and then gets plenty rumpy when in Drive at a stop light. Almost feels like it's going to die but doesn't. It sounds good. I have a dual-plane intake and 600cfm 4bbl and a TH350 with low-stall converter. Even with the tall gears and low stalls, it's still got a good amount more power than my last setup with a 260 cam and stock heads. I'm hoping the 3.40 gears wake it up.
Oh, as for your valve spring question, yes the Xtreme Energy 268 has more lift than the factory Vortec head springs will allow. You will need to change them to "Z28" style (0.525") springs.
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Thanks for all the help guys ;D