I bought a custom cam that got here today, i told them I wanted the 4/7 firing order swap but they didn't charge me the price I was quoted so either they forgot to charge me for the swap or they didn't do it! They are closed right now and I'd like to put my mind at rest tonight if possible, is there a way to tell by looking at the cam? I'm having a hard time matching the lobes to a cylinder number and wether it is intake/exhaust in my head, but from what it looks like they forgot to do the swap, or I'm not looking at it right.... here is the order I am GUESSING, can anyone verify this for me?

Looking at the cam from the front where the timing chain mounts.....

Fuel Pump Lobe
#1 Exhaust
#1 Intake
#2 Exhaust
#2 Intake
#3 Intake
#3 Exhaust
#4 Exhaust
#4 Intake
#5 Exhaust
#5 Intake
#6 Exhaust
#6 Intake
#7 Intake
#7 Exhaust
#8 Intake
#8 Exhaust

This seems wrong to me, I don't know why it just does, so I would really appreciate it if someone could correct me Thanks.

 

Look at the numbers etched on the rear end of the cam. What does it say? Usually that info is marked on the cam.

With the cam out of the engine, just looking at the lobes it is difficult to pick out the firing order. If you put it next to a stock cam from the same type of engine, you should be able to see the lobes which are out of place.

 

Ah yes ofcourse, duh, why didn't I think of that! I have a whole buncha cam's, albeit some very flat lobes, laying around somewhere. Thanks, hopefully they did the 4/7 swap, I don't like having to send things back. And unfortunately theres no mention of a firing order swap on the cam itself nor the spec sheet provided, just says "Cam Motion" and the grind number on the front.

 

If you didn't pay extra for the swap (these cam cores are less used so more costly to build), and it's not marked on the cam or the spec sheet, there's a good chance it's not a 4/7.

Is the grind a "standard" one from that company? I have no idea who does their cams, but not every cam company has 4/7 cores. Comp (and Crane, I believe) are now advertising it, but Comp has had the SBC 4/7 cores for quite a while. Maybe they are now getting them for Brand "F" & Brand "M" and can advetise.

As in any purchase, if you don't get what you ordered, return it for credit or replacement. Of course don't run it in a engine first!

 

The front two lobes and the rear two on any SBC are exhausts in the first place unless you have an LS1 or something like a Ford or BBC. You can marke all the intakes or exhaust and look down the cam as you turn it and see what you're firing order is.

 

The first lobe is number one exhaust and the third is number one intake etc. Just look at the block too and you'll be able to figure it out.

 

Just heard from Cam Motion, they said the 4/7 swap was done and it'll say on the packing slip itself attached to the UPS box, who woulda thought? hehe they apparently made a mistake and charged me $300 instead of $315 so unless they charge me the extra $15 now, I got a discount Thanks guys, and yes I thought the lobes would be in some weird order, it just didnt seem right when I listed them out as above.