Crane Fireball in 68' 383 four barrel?

[StockMan]

I picked up a 68' 383 two barrel motor with 60,000 orig miles.  I went through the motor with new gaskets/seals.  I used the stock steel shim head gaskets.  The heads were a set of 250's, not the 906's but are exactly the same.  145 comp all the way through, 9.2/1 compression motor.  I've got HP exhaust manifolds on it as well. 

I installed the four barrel intake with the correct 4401 AVS 4bbl carb.  I checked the cam and it was stock and had some small differences in the lobe heights and the lifters had flat bottoms (not good).  So, I had brand new Crane FireBall cam and lifters from way back so I decided to install it.  The motor is not installed yet but I have it running on a floor mounted motor setup.  It starts and runs great, idles down nice, good vaccum, a very small lope during idle.

My question is will this cam provide some HP gains over the stock cam?  How does it compare to the magnum cam?  I'm told this cam has more duration and a little less lift and the lobe separation of 112 instead of 113?  The lift on this cam seems to be the same at the stock cam.  And, I didn't dial this cam in, just bolted her in.  Has anyone tried this, or have any knowledge of these cams?

Advertised Duration   Duration @ .050      Lift With 1.5 Rocker Arms   Lobe Separation Angle   Intake Centerline
294/304                      233/243            .440/.456                                 112                      112

Magnum Cam...
Intake Duration, Advert     268/284
Intake Duration @ .050"          208/221
Note: as installed on 113° centerline per Chrysler         

Thanks

[Dans 68]

Welcome to the site. A few of the oldster's will probably weigh in soon with an answer. 

Dan

[Rolling_Thunder]

The stock magnum cam had a LSA of 115* not 113*.

Honestly, I think you gave up some HP and some TQ.  The long seat time (advertised duration vs. duration at .050") kills your low end torque and as the engine is set up now, it can not take advantage of the added duration. The HP manifolds are choking the exhaust side and the heads/intake are really limiting your air intake...   making the added duration a burden rather than a benefit.

sorry to be the bear of bad news   

[StockMan]

This is similar to what I was told by a mopar expert here my area.  If it turns out to reduce the low end to much I will replace it with either the stock or magnum cam.  I might even consider doing this before I put my grill and rad in.  I'm at the tail end of finishing my 68'Charger resto.  The numbers I posted for the cam are from a website I found for the crane 'FireBall'.  The duration seem quite long for the way the motor sounds.  I would have thought that it would have had much more of a 'lope' than it has??  Maybe the posted duration I found is not correct or for a different version of this cam?

This is a two barrel motor (9.2:1) and I do have a correct date coded 4bbl motor (10:1) that I plan to rebuild down the road.  This configuration could get me by until then I guess?  Do you think the long duration will be less efficient as far as fuel goes?  How much of a drop in torque would you estimate here?

Thanks for your reply.

[firefighter3931]

The stock magnum cam had a LSA of 115* not 113*.

Honestly, I think you gave up some HP and some TQ.  The long seat time (advertised duration vs. duration at .050") kills your low end torque and as the engine is set up now, it can not take advantage of the added duration. The HP manifolds are choking the exhaust side and the heads/intake are really limiting your air intake...   making the added duration a burden rather than a benefit.

sorry to be the bear of bad news   

that's a real slow, lazy grind with low lift and too much duration for your intended application, inmo. There are many other modern grinds that would be a huge improvement over that Fireball grind. 



Ron

[Challenger340]

I remember those ! 

I might be "dating" myself, but oh well. 

It'll make way more power than the stock magnum cam @ rpm,
but,
it'll need way more rpm "outa the hole", before it gets going in it's "band".

In a 383, it might be a dawg below 2800-3000 rpm ?

Ron's right again, you may wanna "update".

[StockMan]

This is better news.  So I'll loose some power at the lower end, but maybe gain some on top.  I do have the smallar torque converter that came with the 383 4bbl configuration so this could help a bit with the off the line.  And, I've got the 2 1/2 dual exhaust all the way back, and like I mentioned, I replaced the headers that were on the motor with a set of stock HP manifolds.  So, the HPs would at least be better than the log style manifold for flow.  The motor did like the headers though.

Can anyone recall if these specs I posted for the fireball are close?  Did the fireball have a variety of different setups?  Like I said, the motor runs really nice, excellent throttle response and a hardly noticeable 'Lope' for this long duration.  I wouldn't have installed this cam but I bought it years ago and its never been used and I figured it would have been a good replacement for the 'Wearing' stock 2bbl cam.  When I go to put my 4bbl motor together I'll certainly bring it back to the correct specifications.

Again, your comments are appreciated.

[firefighter3931]

Assuming that your cam data is correct....that combo will want a 3k stall and 3.91 gears to be happy. Don't be xpecting lots of tire frying torque out of this build....the cam is wrong. You can cover up the shortcomings with increased stall and deeper gearing...but it's a bandaid fix.

I would try to verify the exact specs on this grind....call Crane and ask them. There should be numbers stamped on the cam that identify it.

I ran one of those Fireball grinds many years ago...it was my first cam swap in a 383hp motor. Made good power up top but was pretty flat off idle with the stock converter and 3.23 gears.



Ron

[StockMan]

Thanks for your reply.  I'll need to live with this for the time being.  This is my budget motor until I can rebuild the numbers matching 383 4bbl I have.  And again, I'll be sure to get that one done right.  I'm not really the tire smoken kind of guy, more highway driving and moderate city cruising so I should be ok for now.  I have open 323's in the car now, a ways off from the 3.91's.  And the converter is probably a 2200 or so.  The configuration you mentioned would have been the 10:1 motor with the heavier valve springs so going upto the higher RPMs would have worked.  For me this might not be realistic with the lighter springs and lower compression. 

What RPM did your config kick in at?  And did this cam destroy fuel mileage as compared to the stock?

Thanks again...

[firefighter3931]

What RPM did your config kick in at?  And did this cam destroy fuel mileage as compared to the stock?

Thanks again...

Going off memory the motor came alive around 2800-3000 rpm or so. What you could do is go back in and advance the cam timing to lower the powerband. In that combination i would be installing it on a 106* intake centerline. This would help it make more torque lower down and make the engine more fuel efficient. 



Ron

[StockMan]

Excellent, thanks for the advice.  One more thing, I'm curious, when would the stock 383 4bbl come alive?  I believe this had the 10:1 comp, the stock cam with the smaller torque converter and the 323s.  Thanks. 

I forgot to ask, was the rest of your configuration from the past completely stock?  I have stock everything including the HP exhaust manifolds, intake, carb with dual 2 1/4 exhaust.  A few responses ago someone mentioned that this configuration would make the motor unable to utilize the longer duration.

[firefighter3931]

I'm curious, when would the stock 383 4bbl come alive?  I believe this had the 10:1 comp, the stock cam with the smaller torque converter and the 323s.  Thanks. 

The stock 383 4bbl motor used the same cam profile as the 440 magnum.....268/284 advertised duration on a wide 115* lsa. In a smaller motor the power would kick in at a higher rpm and that's why 383's came with a higher stall speed 11in converter from the factory. The 440's all came with 12in converters from the factory and had less stall. The larger motor (440) with the longer stroke will "eat up" the cam duration more so than a smaller displacement (383) would hence the increased stall requirement for the smaller displacement. 


One way to trick the motor into believing the cam is smaller than it actually is....is to adjust the valve timing events. Advancing the cam will bring the powerband in sooner. On an overcammed build this is one way to cover up a mismatched piece and still have it perform well. The wide LSA cam profiles work good with a restrictive manifold type exhaust so you are fine there. Same holds true for the factory 68-71 4bbl manifold which is a descent piece.

Inmo there are 2 things to do to tune this for best performance :

(1) Degree the cam in and advance it at least 6* which would put the installed intake centerline at 106 given that the cam is ground on a 112* lsa.

(2) When setting up the ignition curve i would dial in at least 18* of base timing at idle and shoot for 38* total all in by 2600-2800. An agressive timing curve works very well....especially on overcammed builds.


Here's a good read on tuning a 383 if your interested. It's worth spending the time to "get it right" 


http://1970chargerregistry.com/70messageboard/viewtopic.php?t=1207



Ron

[StockMan]

I'm going to consider replacing the fireball with the stock camshaft before I get my grill and rad mounted in.  Its really not all that expensive.  The other thing I'm concerned about with the FireBall is the vacuum.  There seems to be enough there to operate my AC/heater box and head light doors but what about the distributor.  Will that need to be re-factored for the lessor vacuum?

Thanks

[firefighter3931]

I'm going to consider replacing the fireball with the stock camshaft before I get my grill and rad mounted in.  Its really not all that expensive.  The other thing I'm concerned about with the FireBall is the vacuum.  There seems to be enough there to operate my AC/heater box and head light doors but what about the distributor.  Will that need to be re-factored for the lessor vacuum?

Thanks

If you're going to do a cam swap then you might as well use a good profile. 

Lunati has a cam that would be perfect for your application right off the shelf 

When you read the tuning thread i linked above it will become obvious that vacuum advance is something i never use.....i prefer to tune without it. 




Ron

[StockMan]

Thanks.  I'll check with Lunati for my application and maybe for my other motor as well.

[firefighter3931]

Thanks.  I'll check with Lunati for my application and maybe for my other motor as well.

Here's your cam :

http://store.summitracing.com/partdetail.asp?part=LUN%2D60302&autoview=sku


This is also available in kit form with springs, lifters and the cam. The 60302 will make lots of vacuum and be easy to tune in your 383. Power will come right in at the flash stall speed and it will pull hard right up to redline. Designed to work efficiently with Manifold exhaust systems and stock type builds. This one is a winner and perfect for your combo.

You have a good motor that is mechanically in excellent shape and you don't need to go hog wild rebuilding it....but you do need to rethink that stock broomstick cam. 



Ron

[StockMan]

This cam looks very reasonably priced.  Thanks for all your help on this.

[StockMan]

Thanks.  I'll check with Lunati for my application and maybe for my other motor as well.

Here's your cam :

http://store.summitracing.com/partdetail.asp?part=LUN%2D60302&autoview=sku


This is also available in kit form with springs, lifters and the cam. The 60302 will make lots of vacuum and be easy to tune in your 383. Power will come right in at the flash stall speed and it will pull hard right up to redline. Designed to work efficiently with Manifold exhaust systems and stock type builds. This one is a winner and perfect for your combo.

You have a good motor that is mechanically in excellent shape and you don't need to go hog wild rebuilding it....but you do need to rethink that stock broomstick cam.  



Ron

Thanks, I'm going to pick up the Lunati cam you recommended next week.  I will be installing it into a low mile 1968 440 350hp.  You recommended this cam for the 383 build I was doing at the time, would it be ok for the 440 as well?  This cam looks a little milder than that mopar performance resto cam, as far as duration goes.  (magnum 268/284 and 450/458).  The Lunati has more lift it looks like.  Can I still use the stock valve springs?  Is the Lunati a preferred cam over the mopar purple resto cam?

One other thing, would you stick with the steel shim head gasket or the composite one?  I think this motor was rated at the 10.25:1 ratio.

Thanks again.