300 I-6, NP435 install

[Revelation]

Going to be installing a 300 I-6 NP435 combo in my Bronco, Wanted to throw out some Ideas I am having and see what responses I get.
First i know the 300 is taller, longer and heavier than the 302, My idea to compensate for that is as follows.
1. Set the engine/tranny back 3-4 inches, If firewall issues arise we will cut and move it back an inch or 2, also move the t-case mount back. Driveshafts will be custom built.
2. Drop the engine/tranny down 3-4 inches to lower center of gravity.
3. using this for a weekend ride with about 50/50 on and off road, with the 435 should I go 4:11 or will the 3:50 gears work well? (33 inch tires)
I know I will have to fab the front crossmember for this to work.
I will deal with the suspension by lengthening the wheelbase 1 inch at each end, using poss 4 1/2 " springs in front and 3 1/2 in rear, should sit level with the extra weight.
I am open to advice, I am going with the 300just because I want something different like that. I am starting with a bare frame

 

[wildbill]

;D ;D ;D If you do that I think you will have a bronco that will eat rear driveshaft's like candy. And droping the motor lower you coule end up kissing the front diff.(new oil leak) Just my thoughts on ithave fun. Bill %)

 

[broncnaz]

Get the latest issue of bronco driver they just did a article on this very swap.
You should be able to move the engine back about 3 in before the firewall comes into play. If I remember right a 2in body lift will help clear the bellhousing but you may not need this if your lowering the engine. The 2 biggest problems you will have if lowering the engine is the front crossmember and suspension front crossmember is directly under the engine so to lower you may have to move it farther forward to clear. With engine lower in the frame you may run into problems with the oil pan and front axle so you may need more lift to clear. I dont think the 300 is all that much heavier than a 302 so you may not need the higher front springs especailly if your running a full hard top I've done to lifts on EB's and the front has always been higher than the rear guess thats why some venders suggest going with 1in higher rear springs than fronts if running a hard top and/or a lot of gear. Also you may need a aftermarket intake to fit under the hood unless your running a scoop.
I'd just get the issue of bronco driver and contact the person who did this swap and get the facts from him.

 

[Revelation]

Good input ,
As for the artical in Bronco Driver I have read it about 20 times, The 300 is about 50 lbs heavier than a 302. the 3 inches back sounds like where I need to be, the front crossmember will have to be trimmed about 1" to clear the oil pan, any more mods would cause the aforementioned problems so I will just go with a 2" body lift and the 1" trim on the crossmember, might move the rear axle back a little farther to make up for moving the engine back 3"

 

[Pa PITT]

4:11x3:55

i've ran an 1980 bronco it has 387000 miles now ...300 cid and np435 with 3:55
i"ve had 30x9.50 that i thought were ok with the 3:55s but when i had 33x12.50
i was wishing for 4:11 to each his own but at least with 4:11
i'd even consider the next step if it a off road and week end special ...
just my 2 bits worth
..........PaPitt............

 

[broncoman1972]

I am (slowly) working on this swap now. I plan to use my c4 for now then swap to a 4r70w when I can. I dont have the engine in yet, though since I have been building a storage building/workshop to help with my spread out parts. So far I have removed the engine stands from the frame, cut the crossmember as mentioned, and I have made the initial cuts to the firewall to gain clearance. Granted I will be installing an EFI motor and no body lift, so major mods to the firewall are going to be needed in my case. I plan to start a thread when i get some more progress made in a few weeks hopefully.

 

[Revelation]

As soon as I get the transfer case and tranny rebuilt I will start posting pics of the adapter I will be building then as the project progresses I will post more.
For now I am rebuilding the D-44 9", Transfer case, ans NP435. My Uncle has the motor and Frame/Tub in his shop about 2 hours from me, when I complete the drivetrain rebuild the project will shift to his shop for the build up. That is planned for the end of May when I return from Alaska so I am not to rushed to complete my end. When the buildup starts I hope some of the guys on here who live near Lake City will want to join in and turn a few wrenches on weekends for some good BBQ. (Hint Hint) My Uncle has been working on Broncos ever since I can remember.
But I will post pics as the build progresses.

 

[psbronco]

You probably all ready have a idea/design in mind for your motor towers when you move the forward and down but I thought I would share what I did and what I would change. I moved the frame stands forward about 3" and down some (can't remember exactly how much). I cut the stock front cross member as the welds and slid it forward the same amount. The firewall only required a little of trimming to clear the exhaust manifolds.
It was mentioned front diff clearance, while i was cutting stuff off the frame moved the front axle forward 4" too to avoid any problems. If/when I were do it over I would mount the engine a little lower in the frame maybe an inch or two and notch the engine cross member to fit. The hood is just barely clears.

I took a lot of pictures along the way if you want to see anything in particular.

psbronco

Oh ya I have 3.5" of suspension and 2" of body.

 

[Revelation]

Any pics you want to send would be great. you can mail them to me, I have the general ideas, will be nice to see what others have done, good or bad.
But like I said, any pics or notes would be fantastic, My E-Mail