302 swap on my bronco 2


RagingGumby

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Hey everyone,

I have a 87 bronco 2 with a 2.9L in it. It is a 4X4 manual tranny. This was the first vehicle I ever purchased and I have held on to it for a decade now. I want to overhaul this thing and put in the 302 and whatever else I can do to rehab this beast and make it what I have always wanted it to be. I am finally in a position to throw some money at it but I would still like to go as economic as possible. I am hoping that you guys can help me to let me know what I need to do this. I have been researching and find that I would much rather put a 302 than a 4.0L in it. From what I understand to do this I am going to need new engine mounts and I need to go from the 7.5 rear axle to the 8.5 rear axle. I have also read that I will need a custom radiator and I need to make sure that I get a rear or dual sump oil pan. Are there any other major things I need to keep in mind? I would like to keep it a manual transmission. What transmission should I get that would fit and keep it a manual and 4 wheel drive? I am pretty new to all this so any advice or parts or sites or even a simple order of things would be very appreciative. Thanks!
 


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LiLRanger

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advance adapters or Novak-adapt have a lot of required reading for a swap like this...They even have a step-by step booklet for ya (or at least they did)
 

cammeddrz

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my suggestion? the stock trans will not hold up but your axles might so find a donor truck with a 302, efi, manual trans, and a t-case. usually aquired for around $500 (which is still less than the cost of the adaptor just to adapt a v8 trans to a stock t-case) then i would use the engine, and the married trans/t-case in your bII, only a little modification to your trans cross-member will be necesarry. and then use the driveshafts from the donor truck and have them shortened and the broncoII u-joints installed on the ends. cost me about $60 per shaft at the driveline shop.

all that is left is what turns out to be fairly minor fabrication

and since you are already modifying driveshafts you should find an explorer front dana44 (which will bolt right in place of yours ) and an explorer 8.8 rear which will fit in place of yours by moving the leaf perch from the bottom to the top (or just leaving the bottom un-used and adding one to the top)
 

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my suggestion? the stock trans will not hold up but your axles might so find a donor truck with a 302, efi, manual trans, and a t-case. usually aquired for around $500 (which is still less than the cost of the adaptor just to adapt a v8 trans to a stock t-case) then i would use the engine, and the married trans/t-case in your bII, only a little modification to your trans cross-member will be necesarry. and then use the driveshafts from the donor truck and have them shortened and the broncoII u-joints installed on the ends. cost me about $60 per shaft at the driveline shop.

all that is left is what turns out to be fairly minor fabrication

and since you are already modifying driveshafts you should find an explorer front dana44 (which will bolt right in place of yours ) and an explorer 8.8 rear which will fit in place of yours by moving the leaf perch from the bottom to the top (or just leaving the bottom un-used and adding one to the top)
I'm sure you mean Explorer D35 :icon_thumby:

Also, FYI, the 8.8 swap will not work (well) if you leave the old perches on... at least in a Bronco II... the inner U bolts have to sit at a very extreme angle because the Bronco leaf springs sit slightly further apart than the Explorer ones. I know this 'cuz I tried it.

OP: I'd try to find either the Mazda tranny from a fullsize pickup, or a ZF 5 speed from an F250 with a small block - you can use a T18, T19, or NP435 as well but the shifter ends up under your dash and you may have to do some cutting for it to clear. The Mazda and ZF transmissions shift a lot nicer too. The downside to running either of those is that you are very limited with transfer case options. I believe that a 208 or 1356 will bolt up to either but they are HUGE and will not fit between your frame rails easily or at all. You can run a Early Bronco D20 behind the ZF, they are tiny and very stout, but the adapter is $500. A 205 will also bolt up and will definitely fit between your frame rails, but is very heavy and low range is not really very low.

If you choose to run an automatic, you can use a Ranger/Bronco II C5 which will bolt up to your current transfer case, just get a C4 V8 bellhousing, torque converter, and flexplate for it.

Since you are probably keeping your TTB front axle setup you NEED the dual sump oil pan to clear the axle pivot bracket. You do NOT need to swap rear axles, but it is a good idea to do so anyway to gain the larger pinion flange on the 8.8 just to make building a driveline easy. For radiators you can run a universal or get the James Duff one, and you'll most likely have to run electric fans instead of the mechanical one.

Motor mounts - order from RockAuto - get both sides for an '85 Mustang GT convertible w/ 302. Cut slots or drill holes in your crossmember and they'll bolt right in.

Exhaust - if you are not running headers, you need to take a look through the junkyard and find manifolds that are as close to the block as possible. Usually 70's pickup or van manifolds are OK, Maverick/Comet ones work great too if you can find them. The ones I had from my donor ('89 Crown Vic) stuck out MUCH too far and hit the frame so I used Early Bronco ones instead which work great. You can have O2 sensor bungs welded into your exhaust.

Clutch - I used a '75 Toyota Land Cruiser slave cylinder and built a bracket out of angle iron with the stock master cylinder and hose. Just cut off the end and use a compression fitting for the slave. This was with an NP435 though so if you use the Mazda or ZF, I believe you can re-use the stock internal slave cylinder.

Sorry to be so long winded but there is just a shit load of stuff I discovered when I was doing my swap.
 

cammeddrz

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I'm sure you mean Explorer D35
i had to read my post back again to see that for som f-ing reason i typed 44 instead of 35........:sad:

but everything you said just adds to what i said, i agree totally :icon_thumby: just start with a donor vehicle (like i posted) and then hammer out all the details like shran said. the donor vehicle is going to provide you with most of the big stuff like engine, trans, t-case (hopefully something beefier than your 1354, like a 205) and most importantly your efi intake, wiring harness, computer, and all of the sensors you can use all of that out of it and then sell it to a junkyard or scrapper for $200 for scrap metal and then all of those components only cost you $300. or you can go even further and do a full-width axle swap from the donor truck too........which is a lot more involved. but you'll end up with some much stronger axles
 
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