Crane 500511 or 503901

[Wesman07]

Hey guys I've been trying to decide on a cam shaft for my 1990 ish 300 motor. Im guessing A have about 150k on it now.

Anyway, it in my 86 f150 with and np435 3.55 gears and 35" tires. It is an absolutely great combo! But like everyone else, I want a little more. My two complaints are

1) there is a dead spot when I start off. If the rpms fall slightly below 1,000, it totally falls on its face.

I would assume this is because of the 4 degree retarded cam?

2) I wish it had a little more for those 4th gear hills. When I load up with camping gear and the dirtbikes I'm weighing in at about 6k

On the highway I'm at 2,250 rpm @65 and 2,500 @70ish.

So the question is do I go with the smaller 511 cam? Or the 901?

Can I advance the 901??

 

[pmuller9]

The 503901 will give you the extended power range you need for pulling.
It is your typical RV cam profile for the 300 six.

Does the engine still have the stock EFI system?

 

[Wesman07]

Do you recommend that cam over the crane? Will either one of those cams fix the low end dead spot without advancing it?

 

[pmuller9]

Do you recommend that cam over the crane? Will either one of those cams fix the low end dead spot without advancing it?

No.
I would go with the Crane 901.
The Melling has a very long advertised duration and I've seen at least one review where it did not have the low end torque as expected.

As far as the low end dead spot, Does the engine still have the stock EFI system?

 

[Wesman07]

The only thing I have done was remove the smog system and delete the egr. I am thinking about reconnecting the egr and putting it on a bypass switch. Other than that it's just a good running motor with a mild exhaust and high flow cat

 

[Wesman07]

The only reason I made those modifications was because I was constantly at 3/4 throttle. Now I get around at 1/4- 1/2. It would be nice to have an egr for highway only

 

[pmuller9]

The cam is not responsible for the dead spot just above an idle.
The EGR does lower cylinder temps which reduces NOx but the lower temps also help reduce detonation.
Not sure why the dead spot. The obvious question is: Was the dead spot there before you made the modifications?

 

[Wesman07]

Yes. None of the modifications had any noticeable draw backs.

 

[pmuller9]

Yes. None of the modifications had any noticeable draw backs.

Was the dead spot there before you made the modifications?

 

[Wesman07]

Yes. None of the modifications had any noticeable draw backs.

Was the dead spot there before you made the modifications?

Yes. The dead spot was there for as long I can remember. It is more of a clear drop in power below 1,000 rpm.

I think it has a lot to do with the np435 trans. I start in second most of the time, so it is a fairly heavy load in the motor.

I always had a feeling that if I advanced my stock cam, it would go away

 

[pmuller9]

Yes. The dead spot was there for as long I can remember. It is more of a clear drop in power below 1,000 rpm.
I think it has a lot to do with the np435 trans. I start in second most of the time, so it is a fairly heavy load in the motor.
I always had a feeling that if I advanced my stock cam, it would go away

The way you describe it here would indicate advancing the cam would help.

The stock cam has a long advertised duration of 268* and including the 4 degrees retard puts the intake valve closing point 68* ABDC.
The Crane 901 cam only has a 260* advertised intake duration and if you install the intake lobe center at the specified 108* ATDC the intake valve closes 10* sooner at 58* ABDC.
Should be an improvement at off idle torque.

The down side is that it does make the engine more sensitive to detonation.

 

[Fordman75]

I think it's more the 3.55 gears with 35" tires. Is the dead spot there if you start in grany low (1st gear ) ?

 

[Wesman07]

Ok thanks PMuller9. That was information I was looking for

 

[Wesman07]

It is still there but is less nociable. The truck came with 3.08 rear gears. So when I increased tire size, I re feared it so the finial drive was about the same.

 

[pmuller9]

If you change the cam you need to change the valve spring also.
You would use the Crane 96803 springs and 99946 retainer.

 

[Wesman07]

Ok good to know. Don't I need lifters as well? Or do they come with the cam shaft?

Should I compression test this motor before I ask more from it?

I am a two stroke guy, so this whole cam shaft thing is unfamiliar territory lol

 

[Fordman75]

It is still there but is less nociable. The truck came with 3.08 rear gears. So when I increased tire size, I re feared it so the finial drive was about the same.

3.55's is not enough gear for 35" tires. You really need something in the 4.10/4.11 range.

 

[pmuller9]

Ok good to know. Don't I need lifters as well? Or do they come with the cam shaft?
Should I compression test this motor before I ask more from it?
I am a two stroke guy, so this whole cam shaft thing is unfamiliar territory lol

The lifters come separate. Here is the list.
Crane 503901 cam
Crane 99280-12 lifters
Crane 96803-12 springs (Note: If you don't want to wait till march order 96803-16) you end up with 4 extra springs.
Crane 99946-12 retainers
Crane 99097-1 locks

Yes do a compression check.

 

[Wesman07]

With 4.10 gears my rpm's at 65- 70 would be way too high. I have already thought about it and stregically picked 3.55 gears for my application.

I just drove this truck around the country. It was was fully loaded, weighing over 6k. A 4.10 ratio would have added a few hundred dollars to the fuel bill or a couple hours in driving

 

[Fordman75]

With 4.10 gears my rpm's at 65- 70 would be way too high. I have already thought about it and stregically picked 3.55 gears for my application.

I just drove this truck around the country. It was was fully loaded, weighing over 6k. A 4.10 ratio would have added a few hundred dollars to the fuel bill or a couple hours in driving

It's your truck, so run what you want. But a cam isn't going to fix the gearing issue. The 35's with a 3.55 is very likely your low end dead spot. It would use more fuel with the 4.10 gears. But it will also be a lot quicker accelerating and better for those hills. You are not going to hurt the 300 running it at the rpm's you'd be at doing 65-70 with the 35" tires. But it will use some more fuel. I'm going with the 4.10's in my van ( 300/NP435 ) and I'll be running 32's.

Anyways back to your cam discussion.