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Engine Advice

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MattK

Engine Advice

I have a 1983 Bronco with the Inline 6 and NP435. I have a ZF42 transmission that I plan to install so I can keep the crawler gear and get OD too. It has the stock 3.5 gears (stock 8.8 rear and dana 44 front). I am planning on 33x12.5 R15 tires. If I need to change the ratios I will adjust accordingly.

The question I have is what to do for the engine. I also have a 351W (roller block) pulled from a 91 f150 that needs to be rebuild and will need to be bored 30 over if I use it. I also have carb intake so I can skip the 1991 EFI and computer.

I have a few options I am considering and want some advice. These are in no specific order. I want to keep the costs reasonable. What are your experiences and recommendations.

1) Keep the inline 6 stock (has been de-smoged).
2) Upgrades to the 6.
3) Mild build of the 351W. Bored 30 over. Sniper EFI.
4) 393 stroker kit for the 351w, carb intake with sniper EFI.

My use for the Bronco is recreational day and weekend adventures in the cascades. I don't plan to daily drive it. I also am not making a off road only rock crawler either. I am looking for something that is reasonably comfortable to drive on the mountain highways, FS roads and confidently tackling 4x4 trails. I live in the NW so we deal with hills, mud, and snow. Since it is not a daily MPGs are not critical, but I do want to keep it reasonable.

Matt & Laura (East Wentachee, WA)

Our Ford Family:
1983 Bronco: Restomod in progress. I-6 4.9L with NP435 being swapped with ZF42.
1966 Mustang: Stock restoration with Inline 6
2000 F350 Crew Cab Superduty DRW: 4x4, 7.3 with DP tuner, S&B intake, 4" turbo back, and bellowed up-pipes.
2015 Expedition XL: 4x4, 3.5-liter twin-turbocharged EcoBoost V6

Gary Lewis

Re: Engine Advice

Administrator

My advice is to keep the six, at least initially, to see how you like it. You can always build the 351W later and put it in, and it won't cost any more than going with the Windsor initially. And you may well like the six enough to keep it.

Luckily the two engines have the same bolt pattern so the transmission is the same. But they take different perches, so you can swap out the perches later if you pull the six in prep for the Windsor.

As for gear ratios, I think the stock gearing will be good as the six has good low-end torque so will take off from a stop in 2nd in the ZF pretty well. I'm running 33" tires and 3.55 gears in Big Blue and he pulls away from a stop just fine in 2nd.

So I'd go that way and see what you think. Then if you want more power or need different gears you can make changes based on actual experience rather than what others say. But I think you'll like the 300 six/ZF5/3.55 gear combo well enough to keep it.

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

85lebaront2

Re: Engine Advice

Administrator

I agree with Gary, a little work on the 6 and it will have a load of torque for rock crawling.

Bill AKA "LOBO" Profile

"Getting old is inevitable, growing up is optional" Darth Vader 1986 F350 460 converted to MAF/SEFI, E4OD 12X3 1/2 rear brakes, traction loc 3:55 gear, 160 amp 3G alternator Wife's 2011 Flex Limited Daily Driver 2009 Flex Limited with factory tow package Project car 1986 Chrysler LeBaron convertible 2.2L Turbo II, modified A413

Jake Papageorge

Re: Engine Advice

In reply to this post by MattK

6 main bearings and 7 main caps = one stable bottom end! Torque all day long and a very reliable combination!

It it is torque and reliability you seek, stick with that 300!

I have a 351W in my 85 F150 and I can tell you, for what I do with it (farm truck and pulling the race car and trailer around) I think if I had the option, I would be plenty happy with the 300!

Now if fuel was not so expensive......MOVE EM ALL ASIDE and give me a 460 all day long!

Rembrant

Re: Engine Advice

In reply to this post by MattK

MattK wrote

I also have a 351W (roller block) pulled from a 91 f150 that needs to be rebuild and will need to be bored 30 over if I use it. I also have carb intake so I can skip the 1991 EFI and computer.

Is the 351W engine newer than the truck? I didn't think the 351W roller block showed up until 1994. I know the 302 started getting the roller block (but still with flat tappet cam) in the mid/late 80's, but it didn't get the roller cam until 1992.

1994 F150 4x2 Flareside. 5.0 w/MAF, 4R70W, stock.
1984 F150 4X2 Flareside. Mild 302 w/ 5spd. Sold.
1980 F150 4X4 Flareside. 300i6 w/ 5spd. Sold in 2021.
1980 F100 4X2 Flareside. 351w/2bbl w/NP435. Sold in 1995

MattK

Re: Engine Advice

I am not 100% sure about the age of the 351w block. My friend who is giving it to me thinks it was out of a 1991 F150. But it could be from a different donor. He said it was a roller block. My bronco is a 1983 and the 300 is the original engine.

MattK

Re: Engine Advice

This post was updated on .

In reply to this post by Jake Papageorge

So for the 300 lovers out there what do you recommend doing to it? Leave it stock or make some improvements? If so what improvement do you recommend?

Gary Lewis

Re: Engine Advice

Administrator

You aren't going to get a whole lot more from the 300 than stock w/o doing serious things to it. You can get a bit more "high end" power with the EFI intake and exhaust, but with a stock engine I'm not sure it is worth it. And you could go with an aftermarket intake but again, unless you are going to rebuild the engine, up the compression and change the cam I doubt it is worth it.

My advice is to keep the engine stock, do the ZF5, and see what you then think you need. If you really want to go fast then think about the 351W. If the 300 does the job but you need a bit more then think about some of the options.

Gary, AKA "Gary fellow": Profile

MattK

Re: Engine Advice

Gary,

It was my understanding that the ZF swap causes the drivelines to be modified. If I do all this to add the ZF to the 300 and want to swap to a 351W later is the engine a direct swap? Hopefully the new transmission mounting location does not have to change again. I think the 300 is longer.

Gary Lewis

Re: Engine Advice

Administrator

If I remember correctly I reused the same rear and front driveshafts when I installed the ZF5 in Dad's truck. The ZF is ~1" longer but the shafts still work.

But the tranny doesn't move when you swap engines. The engine moves. The perches for the 300 are very different and in a different place than those for the 351W. You can see the 300 perches on the Pictures tab on the page at Documentation/Exterior/Frames/Engine Perches. I don't think we have the Windsor ones on there, but they are similar to the 351M/400 perches - similar but different so you need the right perches.

Gary, AKA "Gary fellow": Profile

Rusty_S85

Re: Engine Advice

In reply to this post by MattK

MattK wrote

I am not 100% sure about the age of the 351w block. My friend who is giving it to me thinks it was out of a 1991 F150. But it could be from a different donor. He said it was a roller block. My bronco is a 1983 and the 300 is the original engine.

Well make sure, cause the 302 introduced the roller block in 1984/85. The 351W didnt introduce the roller block till 1994/95. Make sure it is a 351W first off cause if it came out of a 91 then it could be a roller just a 302 roller.

"Old Blue" - '56 Fairlane Town Sedan - 292-4V, Ford-O-Matic transmission, 3.22:1
'63 Belair 2dr sdn - 283-4V, Powerglide transmission, 4.56:1
'78 Cougar XR7 - 351-2V, FMX transmission, 2.75:1 9inch
"Bruno" - '82 F150 Flareside - 302-2V, C6 transmission, 2.75:1 9inch, 31x10.50-15 BFG KO2

MattK

Re: Engine Advice

In reply to this post by Gary Lewis

Thanks Gary.

mat in tn

Re: Engine Advice

I cannot really recommend based on an apples-to-apples comparison, but I can speak well of the six. my original truck, which I still drive daily, is the 1986 4.9 with a c6. not really the same but I'm running 32x11.5/15 with a 3.08 gear and no overdrive. it's no powerhouse but good luck stopping it. the only thing that I'm cautious about is towing too heavy of a load for the brakes. I have overloaded it a few times back when I was a roofer and drove very easily trying to give ample stopping room, whether the idiots around me had any concept of physics or not.