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-   1987 - 1996 F150 & Larger F-Series Trucks (https://www.ford-trucks.com/forums/forum28/)
-   -   7.3 vs 351 (https://www.ford-trucks.com/forums/1252375-7-3-vs-351-a.html)

fordcaver91 06-28-2013 05:04 PM

7.3 vs 351
 
ok so I got a 1989 f250 wit a bad 300 in it.. found a 89 351 but also found a 89 7.3.. both are the same price.. its going ta be a hauler so what would be better, cheaper choice?? how hard is it ta put a 7.3 in it??

f100beatertruck 06-28-2013 06:23 PM

I'm assuming you're going to swap motors? If so the 351 will bolt to the existing transmission, making things somewhat easier. Are you going to use EFI? You'll need the 351 computer plus some other things.

Now, the diesel... You'll need a new trans and mounts for starters. I'm no diesel expert but I believe the 89 is mechanical still so wiring shouldn't be too bad.

Are these engines or did you find parts trucks? With a parts truck I'd do the diesel assuming the trans is good from the parts truck. If they're just motors the 351 might be a better choice but a 300 six will be a direct bolt in. Also, the 300 doesn't have to come from an 89. 87-96 should work and earlier may work too. You can use the sensors and EFI parts from your engine. It may be worth while to pass and keep looking for a 300.

FORDF250HDXLT 06-28-2013 07:39 PM

also the diesel is more involved not just due to a different trans,but the fuel tanks and the cooling system.radiator support and larger rad and so forth.with so many idi trucks around for good enough prices.you'd probably be in a diesel truck cheaper just buying one rather than sourcing all the parts.the donor truck would need to a real cream puff 4x4 to be worthwhile imho.otherwise just toss another 300 in her and run it for a while,then buy a diesel truck latter when ready for one.even the old idi's are expensive due to tuning costs and maintenance.not compared to modern diesels,but compared to any of the gas engines of the era.

BigBlockF350 06-28-2013 08:13 PM

For simplicity, I'd just look for a 300. The 300 is also a decent hauling engine with the low end torque that it makes, and it'll make better MPG numbers than a 351.

GNR22 06-28-2013 10:05 PM


Originally Posted by BigBlockF350 (Post 13295581)
and it'll make better MPG numbers than a 351.

Not likely. If it's going to be a hauler, a 300 is going to have to work harder to pull than a 351 in a 3/4 ton pick up. At worst, theyll pull about the same MPG, the 351w may even beat it.

Anyway, 351w is a lot more simple than putting in a diesel. Like these guys have said, in all likelihood, it'd probably be easier and cheaper to just buy a diesel truck if you want to go that rough.

Personally, I'd just go with the 351w given those 2 choices. If you find that you require more power than what the stock windsor offers, upgrading the motor is very easy and relatively cheap.

snowdog79 06-29-2013 09:10 AM

I guess it depends on what you mean by "its going ta be a hauler". How heavy will the loads be? I currently own both a 351 and IDI w/turbo, and have owned a few 300s. I would go with another 300, or if you must have a V8, the 351. The 300 will pull for days if you have the right gearing, and it would be an easy swap. Great motor. The 351 swap will be a PITA as there are many differences like the CPU, exhaust, etc. More power, definitely a lot more top end, but the MPGs are quite a bit lower. Still, I love my 351, mine has been an awesome running motor (179k on it right now). Forget the IDI. First the swap would suck. Most everything under the hood is different - right back to the tranny. And unless you are looking at really big loads (8k+ trailers), the diesel really won't haul that much better, and if big loads are a reality, you would really want to go with a turbo for the diesel anyway. And even then, it's not like it's going to pull like a 6.7 Power Stroke (or any relatively modern diesel).

21411 06-29-2013 01:30 PM

If this is a daily driver work vehicle, fix or find a 300. Motor swaps are not easy. The 351w, will bolt in. Then what? Cooling, exhaust, ac, computer? And don't forget the trans is fine behind the 300, who knows what'll happen with 8 cyl in front now. Your going to want to try that 351 out, trust me. And it'll show the weak points that the 300 was fine with. If its a nice truck, bad motor situation, I suggest fining another truck to work till you can get this one up and running right. Just my thoughts.

GNR22 06-29-2013 01:54 PM


Originally Posted by 21411 (Post 13297029)
If this is a daily driver work vehicle, fix or find a 300. Motor swaps are not easy. The 351w, will bolt in. Then what? Cooling, exhaust, ac, computer? And don't forget the trans is fine behind the 300, who knows what'll happen with 8 cyl in front now. Your going to want to try that 351 out, trust me. And it'll show the weak points that the 300 was fine with. If its a nice truck, bad motor situation, I suggest fining another truck to work till you can get this one up and running right. Just my thoughts.

Putting in a windsor to replace an I6 is much easier than you're making it out to be. You can have your current motor out, and a new one in place in a day. And it is certainly an upgrade from the I6 in a truck that is going to pull loads.

Whatever tranny you have will hold up to a 351w also, unless it already has problems.

garthneddy 06-29-2013 06:20 PM

GNR is right about the 300 to SBF conversion being a lot easier then everyone is making it sound. Having owned both the non-turbo IDI and the 351w, I'd take the IDI for hauling duties but its going to be a very involved swap.

Sapphire Blue_95 06-29-2013 08:25 PM

Like many have said above.....if your hauling heavy loads, take the 7.3. However, it would just be SO much easier to sell your existing truck to purchase a factory diesel truck. 351's are good, but I wouldn't want to use them to haul with. Now why Ford put 351's in some (few) crew cab dually F-350's.....I'll never know. A four door dually is already heavy enough for that engine, then put whatever trailer behind it, and I'm sure it'll be sluggish.

Back to your engine swap....If it's hauling you need, I'd maybe even try and find a 460. You certainly wouldn't get the mileage you'd like, but I have seen a 460 out-pull a 7.3 diesel.

Shawn Hansell 08-05-2017 10:45 PM


Originally Posted by 21411 (Post 13297029)
If this is a daily driver work vehicle, fix or find a 300. Motor swaps are not easy. The 351w, will bolt in. Then what? Cooling, exhaust, ac, computer? And don't forget the trans is fine behind the 300, who knows what'll happen with 8 cyl in front now. Your going to want to try that 351 out, trust me. And it'll show the weak points that the 300 was fine with. If its a nice truck, bad motor situation, I suggest fining another truck to work till you can get this one up and running right. Just my thoughts.

Im kinda new at this forum thing but I'm curious will a 95 7.3 tranny bolt up to a 351?

FORDF250HDXLT 08-05-2017 10:49 PM


Originally Posted by Shawn Hansell (Post 17377747)
Im kinda new at this forum thing but I'm curious will a 95 7.3 tranny bolt up to a 351?

The Navistar International diesel bell housing pattern, is much different than any of the Ford bell housing patterns.The Ford 460 is closest, but it's not a match either.


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