1973 firing order or, 1989?????

broncosport

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May 11, 2005

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349

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Knob Noster MO

• Aug 24, 2008

• #1

I'm stuffing a 1989 mustang 5.0 block and heads, in my 73 with all the 73 extras, water pump, distributor, alt, fan, ect. The thing has a lightning cam in it, stock crank, rods and the pistons from the 73! Which firing order do I go with?? 73 or 89???

 

Viperwolf1

Contributor

electron whisperer

Joined

Aug 23, 2007

Messages

24,322

• Aug 24, 2008

• #2

Your firing order needs to match the cam. I don't know enough about the Lightning motors to say which it is and it may depend on the year. Also if it's a roller cam you'll need to find a steel distributor drive gear. Research the piston fitment before you put them in. Lots of changes to head volume, deck height, and valve relief volume between 73 and 89. You could end up with compression ratio problems or pistons slapping the heads/valves. Personally I think you'd be better off with 89 mustang pistons. They were forged. You may need some custom pushrods with the mix of parts.

 

Broncobowsher

Total hack

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Jun 4, 2002

Messages

34,878

• Aug 24, 2008

• #3

Lightening is a 351. so using a lightening cam, use a 351 firing order. That happens to be the same as the 89 HO firing order

 

M

mattt

Bronco Guru

Joined

Sep 23, 2006

Messages

3,810

• Nov 13, 2008

• #4

The Lightning had a flat tappet cam, so I'm not sure you could use it in an 89 5.0 block because the late 5.0's were roller cam from the factory. Sounds like a mix and match of parts???

I found this topic by looking for firing order. I wanted to verify that a 5.0HO had the same firing order as a 351, thought it did and Broncobowsher confirmed it. Thanks.

 

Broncobowsher

Total hack

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Jun 4, 2002

Messages

34,878

• Nov 13, 2008

• #5

Yes, you can run a flat tappet cam in a roller block. The are backward compatable. Just leave out the roller lifters, dogbones and the spicer. Drop in standard lifters that match the cam and you are ready to go.

the other way around isn't as easy. Takes a lot more work to put roller lifters into a non-roller block.

 

M

mattt

Bronco Guru

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Sep 23, 2006

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3,810

• Nov 13, 2008

• #6

Cool....good to know. On that note, if anyone is looking for a "Lightning" cam, I've got one that was pulled out, and I kept the lifters in exact order for reuse.