289 to 302 information needed.

[lagbolt]

I currently have a 97 explorer efi setup in my bronco and still have the original 289 that came in the bronco in the garage that I would like to rebuild. My 302 in the bronco currently is not doing so good and I would like to prepare myself for when she pops.

My question is can I bore my 289 to a 302 and use all of my efi stuff from my explorer setup? I would like to run the 302 and rebuild the 289 while it is still running, That way I’m ready for when it happens.


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[Broncobowsher]

289 and 302 is the same bore. Difference is stroke and rod length.
Both 4.000" bore
302 is 3.000" stroke
289 is 2.870" stroke
Pistons are the same but the 302 rod is 0.135" shorter.

The Explorer EFI will run just fine on a 289. Being a mass air it will just watch the amount of air going in and add the needed fuel.

Personally, I feel the 289 engines run better than the 302

 

[JKH67302]

If memory serves me correctly, 289s and 302s have different strokes, but same bore. However, you can out your efi stuff on that motor with a lot of parts swaping. I have a 68 302 block with Explorer EFI on it. You will need to run a 351 cam or have the computer flashed to run the old 302 firing order (also match cam sync gear to flat tappet cam). You would need to have the damper re-balanced to 28 oz or get a new one from Damper Dudes for 28oz motors.

I assume your current tired 302 is the Explorer motor. If thats the case I would recommend you rebuild that or find another newer roller block and build that. You would then keep both the one piece rear main and the roller cam.

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[lagbolt]

289 and 302 is the same bore. Difference is stroke and rod length.
Both 4.000" bore
302 is 3.000" stroke
289 is 2.870" stroke
Pistons are the same but the 302 rod is 0.135" shorter.

The Explorer EFI will run just fine on a 289. Being a mass air it will just watch the amount of air going in and add the needed fuel.

Personally, I feel the 289 engines run better than the 302

Gotcha did not know that. Thanks


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[lagbolt]

If memory serves me correctly, 289s and 302s have different strokes, but same bore. However, you can out your efi stuff on that motor with a lot of parts swaping. I have a 68 302 block with Explorer EFI on it. You will need to run a 351 cam or have the computer flashed to run the old 302 firing order (also match cam sync gear to flat tappet cam). You would need to have the damper re-balanced to 28 oz or get a new one from Damper Dudes for 28oz motors.

I assume your current tired 302 is the Explorer motor. If thats the case I would recommend you rebuild that or find another newer roller block and build that. You would then keep both the one piece rear main and the roller cam.

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Yes the 302 is pretty much done. The cam synchronizer got stuck in the block and the part that seats done on the block were the oil pump drive shaft is cracked when removing it, so block is toast.





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[lagbolt]

Motor has a ticking sound coming from the front driver side when it reaches operating temp (180*). I originally thought it was my lifters so I changed them and the push rods but had no change. It’s weird that the motor has no ticking sound until it warms up. Oil pressure is 35-38 psi when could and drops to about 15-20 when warm, sometimes at idle I only see 5-10 and when rpm’s are increased jumps back up to 25-28, of course this is with oil pressure gauge on dash so prolly not very accurate.


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[Rustytruck]

Personally, I feel the 289 engines run better than the 302

I am with you on that the 289 is night and day better than the 302 I would never convert a 289 to be a 302. The 289 wants to run where the 302 is a slug.