Cam.......yet again

[BBillyC]

Okay all you 383 guys. I need a cam. It will be hydraulic flat tappet unless you can convince me otherwise. I want a lift just over .500. My current C/R is about 11/1. Manual brakes. 4 speed with 391 rear. I have just done the heads and block. Pistons are domed. the last thing I need is the cam and this puppy will be driving. So give it your best shot.

Thanks

 

[mcmopar]

Check with Hughes Engines http://www.hughesengines.com or Comp. 2 Comp recommendations are:
XE275HL-10: 231/237 duration @ 0.050 w/.525" lift, 110 deg lobe separation
XE285HL-10: 241/247 duration @ 0.050 w/.545" lift, 110 deg lobe separation.
Both Comp cams are designed with the Mopar lifter in mind and feature fast ramps for added power "under the curve". I have the 275 in my 383 and moparmoose3 has the 285 in his 440. The 285 was featured in a Mopar Muscle 383 build and made 50 hp over the stocker with stock rocker arms. Get a good set of 1.5 ratio roller rockers or a set of 1.6 ratio roller rockers for additional lift. My 1.6 rollers produce .560" lift with the 275's rated .525" lift.
With your compression you could easily use the XE285HL-10. Neither cam is what I would call an "economy" cam but I'm doing ok in that department since adjusting my timing somewhat. You can definitely feel the additional power.

 

[Hoosier Bird]

What heads are you using, do you have power brakes, and how much, if any, did you mill off of the heads? :cheers:

 

[ACME A12]

Both of the Comp offerings that John referenced would be good choices. Don't overlook the Lunati Voodoo options either. They have actually produced a little more power in head-to-head comparsons with their Comp counterparts. I posted a thread with some actual direct comparisons on here months ago if you want to search for them. The 60304LK or 60305LK are probably the ones most closely fitting your stated parameters although Lunati suggests at least a 4.11 gear with the 60305LK. I run Comp XEs in a couple of my cars and like them, but might have gone the Lunati route had I seen the direct comparos prior to camshaft selection. Harold Brookshire of General Kinetics/Comp/Ultradyne fame was hired by Lunati to design the Voodoo cams and I've always been a fan of his - I run a custom solid roller in my Camaro that he designed for me back before he was forced to close the doors at Ultradyne. He's forgotten more about camshafts than the rest of us will ever know...

:jester:

 

[mcmopar]

I've heard about some less that flattering things about the Voodoo cams in Chrysler products. While I can't verify these comments I have read posts on other forums from Voodoo owners who don't like them for one reason or another. Who knows - could be guys who don't really know what they are doing or know how to select the proper cam for their combination.
My recommendation these days is to get a cam that is designed specifically for the large diameter Mopar lifter. Since GM, Ford and Chrysler engines all used different lifter diameters, cams were ground using compromise designs based on the smallest lifter diameter. Since Chrysler lifters are the largest in diameter they allow the designer more mechanical leverage. Also get a cam designed with the newest lobe profiles known as "fast ramp" design. This design allows for popping the valve open quicker which keeps the valve open longer than a cam designed w/o fast ramp technology. And as always, get the springs, retainers and locks specified by the cam manufacturer. After all, they designed all this stuff to work together.

 

[ACME A12]

My recommendation these days is to get a cam that is designed specifically for the large diameter Mopar lifter. Since GM, Ford and Chrysler engines all used different lifter diameters, cams were ground using compromise designs based on the smallest lifter diameter.

In the link that I posted on here previously, Harold states that the MoPar cams in the Voodoo line are designed specifically for the .904" lifter. For anyone that does not know, most cam master lobes were designed with SBC lifter diameter in mind at .842". Not pushing anyone in this direction, I just think that it's helpful to have all of the info so as to be able to make an informed and intelligent decision. Had I not opted to go the stock route with my A12 and purchased a Bob K camshaft, I would probably have given one of the Voodoos a whirl, assuming I opted for a flat tappet... :devil:

:jester:
ACME

 

[Hoosier Bird]

Ok, here's my opinion, like it or not.......... If you have power brakes you need no more than 284 duration to carry the vacuum for the booster, but with the 11:1 pistons (if this is a very acurate measurement) you better be running closed chambers heads in order to run pump gas. 11:1 and a duration of 284 gives you 8.5 dynamic compression. As long as you have closed chambered heads and .035 quench then that cam is perfect and you wouldn't lose any horsepower because of compression but you are right on the max for running pump gas......... If you are running 906 heads then you definately need to go up to the XE294H cam if you want to run pump gas, and if your running power brakes you will need a vacuum canister.......... :cheers: Doesn't matter what cam manufacturer as far as dynamic compression. That all comes from the duration. The rest of the design of the cam depends on what you want to do with this car. Good luck. :cheers:

 

[ACME A12]

Ok, here's my opinion, like it or not.......... If you have power brakes you need no more than 284 duration to carry the vacuum for the booster

I couldn't run power brakes on the gold Duster even with the Comp XE274H...no way, no how...even tried a vacuum canister. Didn't want to spend the money for a hydroboost set-up or even an electric vacuum pump so I just converted it to manual discs. Now the XE268H in the Swinger is a different beast entirely - it works with the power booster just fine... :cents:

 

[Hoosier Bird]

[quote="Hoosier Bird":2vafswqx]Ok, here's my opinion, like it or not.......... If you have power brakes you need no more than 284 duration to carry the vacuum for the booster

I couldn't run power brakes on the gold Duster even with the Comp XE274H...no way, no how...even tried a vacuum canister. Didn't want to spend the money for a hydroboost set-up or even an electric vacuum pump so I just converted it to manual discs. Now the XE268H in the Swinger is a different beast entirely - it works with the power booster just fine... :cents:[/quote:2vafswqx]
But his motor will destroy itself with that cam running pump gas.........

 

[BBillyC]

No power brakes. Good stuff here guys.

 

[BBillyC]

And 906 Heads

 

[mcmopar]

[quote="Hoosier Bird":2mqbju5l]Ok, here's my opinion, like it or not.......... If you have power brakes you need no more than 284 duration to carry the vacuum for the booster

Now the XE268H in the Swinger is a different beast entirely - it works with the power booster just fine... :cents:[/quote:2mqbju5l]

And it sounds like a beast, too
I am using a vacuum canister with the XE275HL-10 simply because right after the car was put back together I started having issues with the brakes and thought it needed one because the brake booster was new. Turns out the booster was bad :crazy: . I didn't really need it but I left it on anyway. It has come in handy but at low speeds I can still run out of vacuum when over exerting the brakes.

 

[BBillyC]

What kind of ligters and rockers are you using with that?

 

[BBillyC]

Lifters.....should spell check before I post

 

[mcmopar]

Comp lifters (per Comp's recommendations), chrome rocker shafts and CAT 1.6 ratio roller rockers (roller tips and needle bearings in the fulcrum area) for a total valve lift of 0.560". I pull around 9"-10" of vacuum at idle with a Holley 750 dual feed/vac. secondary carb modded for 4 corner idle. With a Holley 850 double pumper I get more vacuum at idle (12" +/-). Go figure.
With 11:1 static compression you really need a cam with some duration and overlap to bleed off some of that cylinder pressure or you are going to have detonation problems on pump gas. If you still encounter ping/detonation you may need to investigate using some Max Lead 2000 along with your 93 octane gas. Its real tetraethyl lead - the stuff they used to add to gasoline to make "leaded" gas. I ran it for a number of years in my car and it helped greatly to control ping. Its fairly expensive stuff at $45 per gallon (back when I used it the cost was $30 per gallon but when oil prices went nuts the price increased) but you get it in (4) plastic quart containers that have incremental measurements (oz. and ml. measurements) and a window on one of the sides so you know how huch you are adding. I got my car down to where I was using around 6 oz. per tankful because of my 10.5:1 compression and it ran very nicely. After fiddling with my timing I was able to get the car to run on 87 octane for pleasure driving so I don't use the Max Lead 2000 anymore. If I was going to beat on it I would definitley be running 93 octane gas and 6-8 oz. of ML 2000 per tankful. You can find ML 2000 online here:
http://www.maxlead2000.com/

 

[BBillyC]

Thanks mcmopar....excellent stuff

 

[mcmopar]

Here's a pic just before it went back in the car. The intake, carb and valve covers have all been replaced with other equipment.
[attachment=0:37r9oz3o]Rockers.jpg[/attachment:37r9oz3o]

 

[Hoosier Bird]

If you are running 906 heads then you definately need to go up to the XE294H cam if you want to run pump gas. Just my opinion, and you know what they say about opinions...... If you will tell me what pistons you are running, if you decked the block, if you milled the heads and the head gasket thickness, I'll figure your compression and give you a better guess at what cam you need...........thanks

 

[BBillyC]

I believe the pistons are 30 over TRW L2294 domed. The heads are 88cc and with the .040 Felpro gasket should yield about 10.5/1 CR. I am not sure about the TRW but there is a number inside the piston on the bottom of the dome which if I remember correctly is three digits and the number 203 rings a bell????

 

[mcmopar]

You have the exact same shortblock I have. Is the rotating assembly balanced as well? I also have domed TRW pistons @ 0.030 over. Are you sure they are L2294 or are they L2293? I have the L2293's IIRC. Mine were nicely radiused and polished to remove any sharp edges by one of the previous owners who built this engine.
Here is a pic when I tore it down:
[attachment=0:tse0a5at]short block 2002.jpg[/attachment:tse0a5at]

I am running ported 452 heads, 2.14"/1.81" valves and 88cc chambers but with a set of Victor head gaskets (what can I say? They were in a rebuild kit I had laying around). You'd be fine with the XE285 or XE275 cam. Personally I wouldn't go any bigger than the XE285 cam (241/247 degrees duration @ 0.050). You'll be losing some bottom end with it (or anything larger) but your mid-range and top end will be killer, especially with 3.91 gears and a 4 speed. Having experience with the XE275 with 3.55 gears and a 4 speed trans I can say it is right on the edge of street comfort for my taste. You can definitely run pump gas as I have been running 87 octane with my combination for about 6 months now since I reset the timing.
Jerry (moparmoose3) has the XE285 in his 440 with 9.2:1 static compression, 3.55 Sure Grip and automatic with a stall converter and it runs very well. The 440 can really handle the extra 10 degrees of duration but its a bit much for a 383 IMHO.
I'd give Hughes Engines a call and see what they recommend as well. They've got some nice cams that rival Comp's offerings. Call Comp, too, and get their tech line recommendations as well.