Will an 1984 bronco C6 bolt up to a 1992 4.9L engine? I got all the parts i need for a 2x4 to 4x4 conversion but i don't have the 351 built yet so i want to bolt up the C6 and transfer case to the I6 temporarily. I imagine everything else should work after i figure out how to rig up a tv cable. Also does the vacuum modulator on the C6 need ported vacuum?

-Jon

 

Yes, 4.9 has the 289/302/351 bolt pattern and it will bolt up, you'll just need the proper flex plate.

 

Sounds good that's what i was hoping. As far as the flexplate are you saying the 2 different torque convertors have different bolt patterns? That's no big deal i have the matching flexplate it will just be a pita to get off since i have no air compressor at the garage where the engine is sitting.

-Jon

 

The bolt patterns sre the same. The BALANCE is different and tooth count may be. 300s are zero balanced. 351s run a 28.2 oz-in imbalance. Check the tooth count. The 351 could be 157T or 164T. 300s are normally 164T. The flexplates can only be used with the appropriate sized bellhousings, they will not interchange.

 

So to summerize, if the 351w flexplate has 164 teeth everything will bolt up with the original 300 flexplate. If it has a different number of teeth i'm screwed?

-Jon

 

But it won't have the right balance.