Hey guys I have a 86' F150 4x4 with a C6 tranny that I just got rebuilt and 9" rear end running 4:10's. Will eventually have 35" tires. Right now I have a stock 351W HO with 170,000 miles. It runs great and I am happy with it, but I would like to start over with a fresh motor since I restored the truck. My neighbor has a 390 and two 429 motors just laying around and I could probably get one for either free or very cheap. The 390 would probably take less work to get going because it has ran more recently and the guy said that its a real screamer. 429's ran about +10 years ago, but I dont think that they are seized. I have three choices: 1.) Rebuild 351W and keep it in truck, 2. Rebuild 390, 3.) Rebuild 429. Either motor I choose will get a cam,headers,intake,better carb, and the heads ported and polished. What motor do you think is my best option? Best truck motor? Most power? Will be a daily driver with occasional trail riding and mud bogging. What will I need to swap in one of the big blocks?

 

I'd go wtih the 351W... you will get a lot better fuel mileage from that motor... speed parts are easier and cheaper to find.

 

429...although, i have had a lot of fun with the 390 before...there is no replacement for displacement

 

Along with trying to make them fit, you will need a new tranny to mate behind the 390 or the 429... Keep it simple, build the 351 and drop it back in with no worries.

--Mike

 

351W. Many options available to make this a screamer or a larger displacement low end motor, all without the cost of adapting the other engines.

 

The 351 is your best choice.

 

build a rea motor. scrap it all and get a 460. youre worst bet would be a 390.

 

The F-series of your vintage could be had with a 300, 302, 351 and a 460. A 429 has the same bellhousing pattern as the 460.

So, transmissions for the above engines are almost bolt ins, you might have to change mounts and u-joints and stuff, but it's easier to swap components that the truck could have come with rather than parts that never did.

I assume you don't want to make tranny crossmembers and motor mounts and stuff like that. Doable of course, just a real PITA.

"Most power" would be from the larger engines, the 429/460. Bigger pistons, valves, chambers, etc give you more low RPM torque which in a heavy vehicle like a pickup, is never a bad thing. Let the import cars whine the higher RPMs.

Like others have said, the 351W can be stroked, and it's not that difficult to do. Take the block out to .030", add a 400M crank, 6.125" rods and yo have yourself a 4.170" stroke, giving you about 426cid in a small block format, i.e. a direct bolt-in to your truck as it is now. 6.125" rods can be purchased aftermarekt, or amazingly enough, use Chrysler slant-six rods and some interesting rod bearings. Because of the additional stroke, the forces on the pistons and wrist pins is going to be much larger than stock, so you want to use the lightest pistons you can afford.

Though, I'm going through this now with my 93 crewcab, I'm almost ready to swap out the tired 351W for a stroked 460, giving me close to 500cid. I decided to not stroke all the way out to 550cid, to avoid having to do clearancing work on the block, because I have a pair of turbos that will get installed afterwards. The compression ratio of my 500cid stroker is radically low, anticipating the turbos being installed.

351W stroked to whatever, is your path of least resistance, as you only have to rebuild the motor. Since you're not changing the block it's still a direct bolt-in. Carb and jet accordingly.

 

HOW MUCH MONEY YOU GOT? HOW MUCH YOU WANT LEFT OVER?

rebuild the 351...my 2 penny

 

Get the 392 Ford Racing crate motor and be done, 430 horse and rock solid dependable.

 

Do the 351. You already have the tranny for it. No reason to replace a perfectly good tranny just to swap to another motor. I love my 390 but the money you would spend putting it in your truck could be spent getting better parts for your 351.