Hey guys, I'm recently new around here. I've been rebuilding a 1981 F150 for the last 4 years off and on while going to college and have finally gotten it back on the road this week. (Except for a couple ball joints that just loosened up...)

My next step that I have been debating is what engine to swap out my current 300 with. I'm not opposed to much other than "Big Blocks". (Would prefer to keep it 400 or under) My question for you guys is what you have had good luck with as far as power and reliability. Some engines have a reputation for poor reliability and I'm trying to stay away from those.

Also, another important piece of info is that I converted the TTB to a straight axle and in doing so cut the front lip of the engine cross member. (The part where the power steering cooling tube rest) Would rather not harm my frame because of power, but it seemed slightly over engineered. Any input would be great guys!

 

See my page on engine swaps here: Engine Swaps - ???Gary's Garagemahal. As explained, going from a 300 to any other engine requires a number of changes. I'm particularly fond of the 400 engine, but can't recommend it to you as you have a small-block bell housing pattern. Given that, the only V8's that will bolt to your tranny are a 302 or 351W.

The 351W will give more torque and can be a good truck engine, so I'd recommend it over the 302. You can get more power for the same or less money with the 351W than the 302, all else being equal.

 

Out of curiosity, how does a 289 compare with these?

And you didn't mention the cross member that I trimmed. Should this not be a concern in the process with these engine sizes?

 

It is a smaller 302. Certainly not a truck engine. If you just want to cruise and not tow or haul it might work. But, you must think about your gear ratio. Decode your certification label here: Certification Label - ???Gary's Garagemahal to figure out your axle ratio. 289's and 302's must wind up to make any power, so need a reasonably low gear ratio to be effective, and to multiply their limited torque. Something like 3.50 would be the highest gear that would let a 289 or 302 be able to tow or haul.

I will say it another way: A 302 in a truck won't make it a working truck. I'd never set out to swap to a 302 from a 300, which is one of the best truck engines Ford made back then. So, if you want a truck to drive around but not work, go for the 302. But, even then it won't be fun to drive with the wrong gears.

 

Not sure off the top of my head... But the gear ratio was either a 3.50 or a 3.55 when I replaced the front suspension and differential. They may not have even made the 3.55 but it seems familiar for some reason.

And that answers my question for the 289, I've always been told they are reliable but if they are that low on power I will avoid them.

 

They did make a 3.55 in the 8.8", but it wasn't used in '81 in the trucks. So, you may have a 3.50, but you should still decode your certification label to find out. That's because, as shown here (Towing - ???Gary's Garagemahal), Ford doesn't rate the 302 to tow anything if it doesn't have at least a 3.50 rear axle. But a 300 six can tow with a 3.08.

Towing or hauling takes torque, and torque is primarily a function of the stroke of the engine times the area on top of the piston. All three of the 289, 302, and 351W have a 4" bore, so the area on top of the piston is the same. But the 289 has a stroke of 2.87", the 302 has 3.00", and the 351W has 3.50". (Your 300 six has a 4.00" stroke. )

I said "primarily, meaning if all else besides the bore and stroke are equal. You can increase the torque in a number of ways, such as increasing the compression ratio. But it costs about the same to increase the compression ratio on a 351W as on a 302 or 289, so why start with the smaller engine? It costs less to get the same power from the larger engine than the smaller one. Or, the same money gets you more power in the larger engine.

 

Ahh okay. Not sure why I thought it was 3.55... There was tags on both front ends when I replaced it and the gear ratio was the same. (Thankfully, last thing I wanted on top of a conversion was spend the money on gears also.) Thanks a lot though, it's always nice to get another opinion. I was leaning toward a 351 to begin with.

 

Forget it, the 289 hasn't enough torque to pull a 'sick trollop off a porcelain device.'

289's were installed in 1963/68 cars and 1966/68 Bronco's.

The 1963/64 and early 1965 289's used a different bell housing than late 1965's and 1966/68's. The timing cover and water pump are also different.

IMO, if you must, swap in a 351W. I'm not a fan of the 351M/400, as both were very prone to cracking cylinder heads.

 

This is perfect. I had heard some bad things about the 351M and the 400 but as Gary said neither of those will bolt on to what I have already.

Is it worth just considering a new intake set up and exhaust manifold on the 300 that I have? I mean the truck isn't used for much as far as hauling, I just wanted a slightly better response from it.

 

I always liked the idea of the upgraded intake and carb as well as the later model split exhaust manifolds with dual exhaust on the 300's. A little more peppy without breaking the bank.

 

Depends on your pocketbook and desires. The 300 six is an excellent truck engine, but isn't going to win many races without a lot of work and money. Just perking it up a bit can be done but takes new intake and exhaust manifolds and possibly a bigger carb or two. (Its downside is the long run the intake and exhaust manifold have to make because it is an in-line engine.)

I wouldn't bother with swapping to a 302 as you lose torque at low R's and have to wind it up to make power. Instead, if I were swapping, I'd go 351W to get V8 response, reasonable torque, and good power if wound up.

 

Thanks gary, for the long run that's what I was asking with the upgrades. From other threads I've heard people saying that with only an intake upgrade it doesn't really have much effect.

I was thinking of going with 2 carbs and split exhaust manifolds if I were going to put the money into the 300. I also live in western Maine and they don't test the emissions here, making my options a little easier.

 

I, like Don/WhatsAChevy, would be intrigued with a hopped-up 300, and split exhausts play a big part in that. One of my favorite scenes from Cars is when Doc backs-down going to the stop sign. Such a pretty sound. And, it reminds me of my youth when V8's were too new for the boys to have so they split the exhausts on their inline sixes.

 

This site has some very interesting discussions and info on I6 performance.

https://fordsix.com/viewforum.php?f=...1a3a453f4246fc

 

Doc was a Hudson Hornet.

1952/54 Hudson Hornet's with the 308 cid flathead 6 and dual carbs dominated NASCAR .. soon became known as the Fabulous Hudson Hornet.

Jack Clifford, well known for hi performance 6 cylinder parts got his start offering speed equipment for these engines.