rebuild 302 or swap in 351?

[wap13]

I know there are some ford guys on here so....

I have a 91 F150 thats pretty well worn out. I need to put an engine in it. I've never liked the 302 thats in it but to be fair I got the truck at least 3rd hand and it never ran very well for me, so I'm not sure what a fresh 302 would feel like. I always wanted a 300 or 351 as its a farm truck and I need the low end torque off road more than hp on the road. Side note, I have a 300 from a 92 I could build or use as a core if thats a viable option but being a different platform all together (i6 vs v8) I assumed a 351 swap would be easier. Mainly in the wiring and ecm.

Anyway, I can put a crate 302 in pretty cheap and easily OR look for a 351 and install that.

My question is, if I find a 351 of the same vintage is it pretty much a bolt in affair or is there more to it? Would the computer work for a 351 or would I need to get one for a 351? I could swap to a carbed 351 but would just assume stay efi if possible.

Truck is a 5 speed and I swapped in a zf5 years ago (best thing I ever did) if that matters.

Thanks for any input

 

[Woodslasher]

My two bits, my dad had a 1993? ish F250 4x4 with a 351, he said that thing was so much of a dog he sold it and kept his 69 F250 with the 390. I can get more details later but for now I just know that the 351 was very underwhelming in his opinion.

 

[Tim N]

I had a 1990 f250 with a 351. Most underpowered truck I ever owned. I ended up dropping a 460 in it. Alot of work but well worth it.

 

[wap13]

I appreciate the input. If yall think the 351 is bad try a 302.... I'm not doing a big block. The truck is a single cab short bed and very light. Plus my zf5 is a small block. I dont doubt the 351 was lacking in 3/4 ton trucks, especially IF they were autos. Now days the autos have come up to speed but comparing any engine with a standard trans and something like a c4, e40d, etc really isnt fair.

The truck is a true beater too. I kind of hate to put any money into it but it keeps me from beating up any of my "nicer" trucks. And while we dont have salt on the roads down here I do put out mineral and salt for my cows and I hate getting that on anything else.

Again, thanks for the .02

 

[JimBear]

I had a early 90’s F-250 with a 6 cylinder & a 5 speed. We mounted a bale spear on the back & I hauled 1500# - 2000# hay bales with it & pulled a 16’ livestock trailer with it. It wasn’t a power house but worked effectively as a farm truck.

I also had a 96 F-150 with a 302 & auto trans, it ran to 296k before the frame rusted out & engine crapped out.

My current 97 F-250 has a 351 & auto trans, definitely not a powerhouse but serves its purpose as a farm truck hauling wood & pulling trailers.

I had/have no problems with torque in any of them that’s what the low range is for.

That said I would either stick with the 302 or go to the inline 6.

 

[Kiwioilboiler]

@Steve

 

[Maintenance Chief]

Im a big fan of the strait 300 for work, with a stick they are a real work horse.
If you do go 302 or 351 a set of HP heads from a mustang or 1969 small chamber 351 heads are a good way to wake the up.

 

[wap13]

Im a big fan of the strait 300 for work, with a stick they are a real work horse.
If you do go 302 or 351 a set of HP heads from a mustang or 1969 small chamber 351 heads are a good way to wake the up.

Always wanted heard that about the 300, hence why I'd like to try one. Just not sure if the swap would be worth the hassle. Other than engine mounts and some of the wiring I guess I should look into what else is involved in the swap.

 

[blades]

Those 300 6's are in just about everything. there were 2, 351's one was a longer stroke than the other. been so long think one was a cleaveland and the other a winsdor. the long stroke was for heavy trucks and some other commercial equipment.

 

[JimBear]

In the older Fords, 70’s - 80’s there were three types of 351’s. If I remember correctly they did away with the M’s & Cleveland’s but I may be mistaken.
The Windsor hung around until the 90’s
The Windsor, Modified & Cleveland.
Windsor was a small block
Cleveland & Modified were a large block, they made a 400 & 351 modified.

 

[wap13]

Surprised the 351 aint getting any more love. I would be looking at a windsor from the same vintage of truck. No need to try to make a cleveland or modified work.

 

[Funky sawman]

I'm a big fan of the 351. It's all in the gearing, with proper gearing it will pull good. Most f250 with Windsor had 3.54 gears which sucked for towing. My f250 with 3.54 gears works great because it's sporting a 460 4 bbl. The Windsor has a taller deck hight than 302, and I think the flywheel is weighted differently. Not sure if front accessory brackets will swap with the different deck hight.

 

[Maintenance Chief]

I think it's really about yoir intended purpose for the truck. From what I read it's more about farm work and thats why I suggested the 300-6 .
If you needed to get somewhere fast I'd suggest the 351 Windsor or early Cleveland ( see Boss motor) . Hell even a warmed up 289cid can put out 271hp at 475 pounds !

 

[ElevatorGuy]

If you want it sporty rebuild the 302, building it for a work truck throw a 351 with a mild cam and a shorter rear gear.

 

[Duce]

Just drop a Ford voodoo V8 in it, that should work for work and fun.

 

[Steve]

@Steve

Ok Adam, I'm here now!


So the stock computer system is very basic and can barely compensate for 10% +/- airflow differences. So you would have to use a 351 computer if you swapped in a 351. The 302 computer could not support the fuel requirements for the extra displacement. Keep in mind that none of the truck engines from this time period were hot rods. They have one job and that was to haul loads reliably. Speed of hauling was last on the list.


I have been driving an 88 f150 300 5 speed daily for almost 6 years now. It keeps up with traffic just fine and hangs with everyone on the highway too. It is the lowest hp engine at 150hp brand new! The 302 has a bit more hp, I think 165ish? But shares the same torque at 260ft-lbs with the 300. The 300s have their weaknesses though. Everybody lugs the *s-word out of them because of their high torque at the expense of the bearings. High load at low rpms means low oil pressure and premature bearing wear. There are also 13 bearings on the crankshaft. That is a lot of areas for the pump to lubricate. Good rule of thumb is to keep it over 1500rpm when driving and you will have plenty of oil at the bearings. Here are the bearings out of my original engine with 112k on them! Grandpa liked to lug it.

 

[Steve]

@Steve do you know what oil your grandfather used?

He bought this truck brand new when I was 2. I'm sure every brand was in it at some point. My salvage replacement engine was the same way. No idea on milage or oil history. My rebuilt original engine runs Valvoline 5w30 synthetic.

 

[Sagebrush33]

l6 for the win here. Great on fuel too.

 

[Steve]

Repeatedly starting an engine in sub-freezing temps with budget oil that flows like molasses will make the bearing look like that in 100,000 miles.

Don't forget that by today's standards all oil in the 80's and mid 90's was budget oil.

 

[Kiwioilboiler]

351 Cleveland development has been furthered greatly by the Australians, where that engine is very popular due to its success in Ford Falcon GT H.O. road and circuit race cars thru the 70s and 80s.
For whatever reason it's 90 degree block just wasn't as popular stateside by the looks.