I picked up a 71 Grande last week. The guy I got it from knew very little about it; most of the work on the car had been done by the previous owner. I was under the impression that the 302 motor was essentially stock except for some chrome valve covers and a carb upgrade (Edelbrock 1406 on a Performer 289 intake manifold). However, while chasing down an ignition problem (bad coil) I was surprised to find it had a firing order for a 351. I ran the part number on the distributor and confirmed that it was for a 351W. The block is definitely a 302.

I'm a bit of a noob, so I'm looking for some suggestions as to what might have been done here. Is it common to drop in the crank & cam for a 351 into a 302? Is this possibly part of a stroker mod? I'm looking for suggestions as to figure out what might have been done without having to tear it down.

 

The late model 302's used the 351 winsor firing order. It looks like someone put a late model cam in your motor. None of the internals have to be changed to run the newer cam, just the cam and I assume new lifters.

 

Sounds like you have a 302 HO, they were the only other engine to use the 351 firing order.

 

many aftermarket cams for the 302 use the 351 firing order.

 

For sure one of the above two answers apply... (edit.... now three.... yea it took me a while to get this out)

a. The engine has been swapped out to a later HO motor and/or

b. The cam has been swapped out. Many aftermarket 302 cams will use the HO/351 firing order, I think this is done mainly so the cam company can stock one cam for all three applications.

Not a big deal, the ONLY thing that accomplishes this (on a non-fuel injected motor) is cam selection and placement of wires on the distributor cap

 

Thanks for the suggestions. I'm replacing plugs in a couple of days so I'll measure the stroke to see if there's anything interesting there. The engine is clean and dry so I'm just hesitant to open it up since it won't achieve anything other than satisfy my curiosity. The only change I'm looking to do short term is to replace the distributor with something without points, e.g. Duraspark II. Since the firing sequence is different it kind of threw a wrench into that plan until I better understand what I'm working with. Thanks again-

 

Different firing order doesn't hinder the distributor choice.

 

To elaborate, the ONLY implication of the late firing order, (as far as the distributor goes), is the order in which the spark plug wires are placed around the top of the distributor cap....

Everything else (like the cap, rotor, and the entire distributor) can be exactly the same whichever firing order is used.

 

Thanks- I was looking to make sure there weren't any physical differences with the distributor; you've cleared that up. Hopefully the ignition upgrade goes smoothly.