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Old 11-09-2012, 12:59 PM
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Originally Posted by Bronco75 View Post
I have a been working on a 1975 Ford Classic Bronco for some time now. I have built a 302 engine which I tought would perfrom better than it does.

I had a solid lift cam built. I told them all the variables of my engine and they built me a cam to match. so I fugured all was good, but I am not impressed at all. I do have a few issues that I know I need to correct, but here is the question.

The cam I had built has a 351W fireing order, so looke up the correct firing order for a 351w and used that. But I did buy a MSD Dist. for a 302 if i remeber right
The distributor is fine. Just be sure the firing order is correct for the cam- if you wired it wrong, like for the non HO 302, you'd know it- it wouldn't run, period. Info on Ford firing orders can be seen here.

The cam specs and ignition timing specs will help, but it's a very good chance you need more initial timing. Take a look at the info here on timing. Even though the page was originally written about the GM HEI, the timing section still applies to you.

The problem w/not using enough timing is caused by the overlap, reversion and late intake closing point that gives a high performance cammed engine that sound we all know and love. The fuel/air charge is diluted and very lean. This means the ignition timing needs a lot more advance than a stock cam to get that lean charge lit soon enough that it is mostly burned while it can still do work inside the cylinders.

Other things that could be a problem is if the engine wasn't built w/enough compression for the cam, or a too-tight torque converter, or too high rear gears. Carb tuning can cause problems, fuel delivery has to be adequate, even something as simple as a bad plug or plug wire, or a carbon tracked or cracked distributor cap can cause problems like you have. And on and on. But for now I'll see what you can add to help diagnose this.
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