170 3 speed swap to blueprint bronco efi/auto

[iSense67]

Have a 1967 bronco and looking for any advice as I am meeting with shops to swap my 170 six to the bronco full dress 306 efi/auto? My question is should I be thinking about different axles or gears to optimize the swap? At the same time I will have disc brakes, power steering and AC installed. My goal with this post question is I want to make sure I have them set up right to optimize the transition. Also would be interested in hearing of others are happy with the blueprint 306 auto package, ie performance, Highway abilities, how smooth is the 4 speed shifting ratio? Any other wisdom?

 

[DirtDonk]

I think to better answer you, we need to know what gear ratios you have in the differential right now, and what size tires you are ultimately going to be using.
That would be a good place to start.

 

[iSense67]

My current appears to be original/stock and my tires are 15’s and I am not planning on lifting as I this will be a driver not a climber. Here Is a photo of rear and front

 

[Broncobowsher]

Those axles are stock. But stock had two choices for the 170 engine. Base were 4.11 gears and optional were the 4.57 gears. Need to know which gears you have as either could be "stock".
15" is wheel size. We need to know the tire size of what you are planning on running.

Once we know that, there will be better answers.

Taking a SWAG at it, I am going to guess the axle gearing might be fine *IF* you select the correct transmission. The little 170 lacked torque and that is why they had such low gearing in the axles. Since you will be putting in an engine with a lot more torque, less gearing is needed to make it drive good. Since you are looking at doing a transmission swap at the same time there is a real good chance you could put in an overdrive transmission and that will fix the gearing issue. A 6R80 would be my go to choice at the moment, this is an update for the 4R70W that I have liked for the past couple of decades.

 

[DirtDonk]

Yes, sorry I just reread mine and it must’ve been late. I always try to review my text auto spell when I am ready to post. Guess I missed it that time
Instead of “Gary shows” or whatever it said, it should have read “gear ratios” instead.
Fixed it for now, but Broncobowsher cleared it all up.

 

[DirtDonk]

And for just a little bit more information for your list. Those original differential assemblies are a Ford 9-inch in the rear, and a Dana 30 in the front.

The 9 inch is also an earlier version, where probably 67 was the last year for it, that has a fill plug on the back of the housing. Later models did not have that and had to put gear lube in through a small sight plug in the front casting.

In mid 71 they changed to a Dana 44 in the front. Otherwise the 9 inch was used in the rear all the way through about 83 or so.

 

[okie4570]

What's the axle code on your warranty tag on the driver kick panel? Top row, far right two digits or a letter and a digit.