493 Cam Selection

[Purple68]

  Hi guys, first post here. I've been lurking for some time and have learned a great deal on this forum.
I recently got my car back together after several years and just fired the new engine a couple weeks ago. Unfortunately a problem developed the next day and the motor is back out again.(one bolt cam sprocket sheered pin off and went out of time) I think the cam was too small so I'll probably change it while the motor is out. Here is my combo:

68 Charger..probably got the weight down to about 3600#s
493-RPM heads and intake
10.5 compression
850 vac sec Holley carb
2" headers
727 w/ tight 10" converter
4:10 Dana

This car is going to be 99% for the street and some road trips 60 miles or so. I have power brakes and don't want to change to manual, so vacuum is important.

Thanks in advance,
Robert

[c00nhunterjoe]

aside from the cam swap, trade that vaccum secopndary for a mechanical...... you will be happier with it.

for the cam you have alot of choices with those heads and intake. how much valve clearnace do you have? that will make a big difference in your cam choice.......  but with vaccum in mind you are somewhat limited but not too bad. get a reserve canister and you will be fine. stick to the 230 at .050 duration and you will be fine for vaccum use with a canister.

[Purple68]

Thanks, I guess for reference I should have posted the specs of my current cam.
It's a comp XE274H

dur@050 inch Lift  230 int./236 exh.
.488 int./0.491 exh. lift

I didn't build the engine so I'm not sure about piston to valve clearance at this point.

As far as vacuum with the current cam, I didn't check with a vac guage but the brakes worked great.

[Challenger340]

The 274 is REALLY small for a 493 !

Remember, as the engine gets bigger, so does the Cam requirements. Strokers eat up duration @ .050 very fast.

With the 4.10 gears I'd opt for an xs282 solid, and add a cannister for the brakes, just my opinion.

[firefighter3931]

The 274 is REALLY small for a 493 !

Remember, as the engine gets bigger, so does the Cam requirements. Strokers eat up duration @ .050 very fast.

With the 4.10 gears I'd opt for an xs282 solid, and add a cannister for the brakes, just my opinion.

I agree with Bob, the XS282S would be an excellent match for your build. It will make loads of vacuum for your power brakes. I would even consider ordering a custom version of this grind with a wider 112* lsa to spread the power out and increase manifold vacuum and mellow out the idle.



Ron

[Purple68]

I'm not to sure about going with a solid cam,but I'm gonna think about it.   What do you guys think about this hydraulic cam?
Dur @.050 241/247
.545 lift, 110 lobe seperation
This is the second biggest cam 440 source has on there website.

[Challenger340]

I should start off, by confessing that I'm not a fan of Hydraulic Camshafts.
That said,
That Stick doesn't look terrible, just be aware that in a 493 Inch Engine, expect that when you Dyno the Engine, you are Dyno'ing aren't you ?
It's Peak Horsepower event will be all done by around 53-5500 rpm, and that would be WITH worked/ported Eddie Heads.
Not, that it won't rev higher,
it will,
just that won't be much point going much higher, once you are past "peak power" ?

Peak Torque would be waaayyy lower obviously, in low 4,000's, not a bad thing.

I still like Ron's suggestion of ordering the xs282 on the 112 lsa, just makes sense to me,
but the 440 source Cam will work fine and should drive nice.
Have you thought of going to 1.6 Ratio Rockers with that Hydraulic ?

Just my opinion, bob out.

[Purple68]

Thanks for the input, I'll have to think it over a little and decide. I will definately consider the solid cam. I just had the motor built and it has new 1.5 Comp roller rockers already so I don't want to replace them now. I guess they'd work well with the solid cam that was suggested, right?
The motor won't be going on a dyno as there is not one anywhere near me.

[67_Dodge_Charger]

The RPM heads have a .600 limit of lift, so with the 10.5 compression you should not see any valve piston problems unless you push the edge.  You will have a strong motor with tons of torque.  Ron is a great source to have on our site.

[firefighter3931]

Purple....Go with the solid cam, better valvetrain stability at higher rpm and you don't need to worry about lifter collapse. The 1.5 Comp rockers are fine with that cam and the stock E-head springs are also compatible. Hyd stuff becomes unstable past 5500 rpm as Bob mentioned. The 112* lsa will extend the powerband a few hundred rpm vs a 110* grind so that is a bonus....not to mention the improved street manners and idle vacuum (easier carb tuning)

I also like the EDM lifters with priority cam lobe lubrication....well worth the extra few dollars to protect your engine. A switch to solid will also mean new pushrods but that's no big deal.....just the price you need to pay to make power. 


Ron