I have a 1978 F150

Originally has a 351M in it (pretty much dead, in need of serious rebuild)

4 speed granny gear

i have a chance to buy a 460 for $200, and the catch is its locked up the guy said someone was rebuilding it left one of the valves opened and water got in the block causing it to lock up. He said the radiator was off along with the water pump so the system may have drained the water. Should i take the chance on this 460 since their is a possibly that the block may be cracked? i plan on rebuilding for the block up anyways.

Give me some advice people

and how hard will the swap be? it comes with engine mounting brackets

 

If it's a truck engine, (with the truck pan and exhaust manifold you'll need for the swap) its a fair buy even if the block is cracked. The 460 block is pretty beefy. What are the details with the engine? Is it rusty, were they taking it apart outside and left it? How long has it sat?

I'll be doing the same swap as you soon, you'll need;

-460 swap mounts, don't fool with the 35m/400 mount adapters

-Get all the accessories you need from the 460 like power steering and alternator brackets, if these don't come with the engine, you can buy them to mount your 351m/400

-Get the correct 460 flywheel for you engine, if it is 78 and older its internally balanced, if 79 newer its external. 351m/400 flywheel will not work.

-Diaphragm clutch for 460 to clear bellhousing

-Bigger radiator unless you have a the large Desert runner radiator, it will be 4" wide at the top tank

-You can reuse you 351m/400 Distributor and starter unless they are old and worn out

-Headers if you intend or don't have truck manifolds. L&L's are very nice and you can get long tube in frame, Fenderwell, and shorty headers. Maddog makes a nice set of fenderwell's too.

Truck/Fox Mustang Oil pan if you don't have one from your core.

If you want to spend a ton of money but have it all in one kit, L&L sells a complete kit. You can piece it out, Bronco Grave Yard and L&L have all the pieces individually, It depends on your core and what you intend to do with the truck and your expectations from the motor.

 

If that block is cracked, why would it still be a good buy ???, cracked blocks easy to fix or something.
Neil

 

Because you can find a replacement block. It also depends on what come with the motor, like a truck pan, manifolds, brackets for accessories, flywheel, Older heads, Alum intake, etc. but with out more information......

 

the motor was being built outside, sat out over last winter with valve covers off and breather and radiator and water pump all off. What will i need to be able to do this swap i need detailed info plz

 

from L&L would i need the complete kit or just the rubber things and the alt/ps? and would this make it to where i would not have to weld and cut of the inside of the firewalls and stuff/supports?

 

Is your truck a 4x4? (for some reason I thought it was) If it is a 4x2, you have other options as the 460 came stock in a 2wd. The 460 is a direct fit for your frame stanchions (sp?) and bell housing. There are decisions on your part that need to be made and depends on what you have to start with. Does the motor have the accessory brackets? Does it have a truck or car oil pan? Are you going to run manifolds, if so does this come with them and are they truck manifolds? With the correct 460 swap mounts, flywheel, clutch, and pressure plate, manifold/headers, the 460 is a drop in for your 351m. An Iron head and intake 460 weights about 720lbs and your 351m weigh about 570lbs, so you might consider some leveling springs if your not lifted. If you just have a core engine of block, heads, crank and rods, (ie, no pan, accessories, or exhaust manifolds) the L&L kit will be everything you need to install the 460 and swap all your 351m's accessories. Here is sites for some food for thought.

Installing a 460 -- The Right Way!

Use the search function on this site in the 460, engine swap and 73-79 forums, there is a wealth on knowledge on the subject. The 460 to 351m/400 in the most common and easiest swap for the 73-79 trucks. You will not need to cut or weld anything in the engine bay for this swap.

 

Brackets are a real pain if you are working on a 77.5-79 f250 4x4. The common low mount alt bracket wont work, hits the cross member. Some people flip the alt around and use some sort of top bracket but I've never came across one even if I did I wouldn't have used it cause it's too high up making it so it has to run off both the crank & water pump pullies which doesn't leave much for the belt to ride on the alt pully. It probably would slip under a good load.
The power steering pump brackets are a problem as well unless you are going to run the air set up. I wasn't so I turned to the 3 bolt draw style & had lots of problems. I had to remount it higher and angled it some and made a adapter for the botom water pump bolt but that wasn't the end yet, it was still tight so I ended up cutting a chunk out of the end where the draw bolt goes through and moving it back and welding it back in so I could get a short enough belt in to make it all work
Good luck.

 

its a 4x4, the motor comes with a pan

 

its a F150 1978 4x4