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Discussion Starter · #1 ·
I am building a 302 for my father-in-law to go in a '65 Mustang fastback. He wants smooth, mileage, and power in that order.

What i am going to do is use a Lunati Voodoo hydraulic, 61000, about 9 to 1 flattops with the '70's 302 heads with a little cleanup and a performer intake, with 289 hipo manifolds. The carb is a 520 cfm Autoite 4100 off of my '65 352. It should be really good from idle to 5000, and with a 3.00 gear and a C-4 I think it should be about right.

What I'd like to know is besides smoothness, what is the advantage of the 137... firing order? If it is a big advantage, I'd like to get a custom cam ground for an FE.

Thoughts?
 

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It takes some of the load off of the #1 main bearing by not firing the front cylinders one after the other.

<font size=-1>[ This Message was edited by: scottford351 on 8/29/06 11:18am ]</font>
 

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Hmmm now im confused, I thought that the later 5.0 revised firing order was 154 and the older one was 137??
 

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Takes the load off of the front main and places it on the rear main. Its the only difference that I could ever notice.
 

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On 2006-08-28 22:13, 71hotrodpinto wrote:
Hmmm now im confused, I thought that the later 5.0 revised firing order was 154 and the older one was 137??
Well, it depends.

The 5.0L HO engine was used in 1983-1995 Mustangs, Mark VII Lincolns, and some T-birds and Cougars. All Explorer 5.0L engines are 5.0L HO engines as well. They use the 351W firing order, 1-3-7-2-6-5-4-8.

The 5.0L non-HO engine was used in 1982-1990 Crown Victoria and Grand Marquis. They use the 289-302 firing order, 1-5-4-2-6-3-7-8.

The 5.0L Truck (except Explorer) engines also use the 289-302 firing order, 1-5-4-2-6-3-7-8.
 

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Frankly, you are going with a carb so it really doesn't matter much. Firing order is only an issue when you use EFI. On EFI the order has to match between the cam and the computer. A carb dumps fuel to all cylinders at the same time. Properly installed and adjusted both firing orders will run well.
 

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Ok, but doesnt the cam play a role as to when the distrubutor fires?
For example i have a B303 cam. I havent fired the car yet as im still under construction.
So dont i need the later model firing order to match the cam?
 

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"Takes the load off of the front main and places it on the rear main. Its the only difference that I could ever notice."

Actually it puts the load between the #3 thrust main bearing and the #4 main bearing - much stronger.
 

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I don't know about the Hi-Po manifolds but the Tri-y headers are tuned to the 289-302 firing order. Long tube headers are not.
 

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On 2006-08-29 07:12, sweetstocker wrote:
It doesn't play a role as to when the distributor fires each plug (how you run the spark plug wires determines that).

The cam's firing order makes sure the valves are in the right place when the distributor is firing.

But, to answer your question, the B, E, F, and X Ford Racing cams are all 1-3-7-2-6-5-4-8 firing order.



<font size=-1>[ This Message was edited by: sweetstocker on 8/29/06 10:15pm ]</font>
Ok well my point is that the cam determines the firing order not JUST the efi sequential sequence. You cant just run a (For example) b303 etc cam with the older firing order that it wasnt designed for.

RIGHT???
 

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i better get my headers retuned.
dont these 2 blocks have different cranks that dictate what cam you must use? or is it just the cam?
 

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Just the cam... the 1-3-7-2-6-5-4-8 and the 1-5-4-2-6-3-7-8 use the same crank. Look at it closely... only the 3-7 and the 5-4 switch places.

When 1 is at TDC, so is 6 (but on the exhaust stroke).

Next, 3 and 5 are at TDC. Next, it's 7 and 4 at TDC. The cam determines which of these is on the compression stroke and which is on the exhaust stroke.

On 2006-08-29 20:51, 71hotrodpinto wrote:
You cant just run a (For example) b303 etc cam with the older firing order that it wasnt designed for.

RIGHT???
Right... if the cam is setting up cylinder 3 with fuel and you have the distributor wired to fire cylinder 5, it won't work quite so good.

<font size=-1>[ This Message was edited by: 89Trooper on 8/30/06 12:46pm ]</font>
 

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Discussion Starter · #14 ·
My brother-in-law rebuilt a 351W for a customer and got the wrong cam, a 302 154... order. He wired it up with the 137... order, and it barely ran.

So to be clear, the firing order must match the cam.

I think the cam is coing to work pretty well with the manifolds, and it has duals with a H pipe. And it is a dual-plane. As was stated, the carb should supply just fine.

Thanks everyone.

<font size=-1>[ This Message was edited by: BillBallinger on 8/30/06 8:35pm ]</font>
 

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On 2006-08-29 13:08, abecerra wrote:
I don't know about the Hi-Po manifolds but the Tri-y headers are tuned to the 289-302 firing order. Long tube headers are not.
It doesn't matter.

289 firing order: 1 5 4 2 6 3 7 8

5.0 HO firing order: 1 3 7 2 6 5 4 8


Tri Y headers pair the cylinders as follows:

1-2: 270 deg apart with both firing orders

3-4: 450 deg apart with both firing orders

5-7: 450 deg apart with both firing orders

6-8: 270 deg apart with both firing orders

Also note that all combinatoins are always divided 270-450 (or 450-270, depending on how you count)
 
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