360 into a 390

[jay1213]

I know what is needed 2 do this swap, a 390 crank. My question is I've looked up reman 390 cranks at work(bc all the local yards have no fe motors) I have different casting numbers on the cranks I'm looking up, what number should I use????

[fordman]

i woudl guess that it depends on wheather you want to build it to car specs or truck specs.

[jay1213]

I would imagine I would want it built to truck specs? I'm just looking 4 that extra oopmh, and I get the crank 4 about 100 bucks, and the engine work is done by me so....

[fordman]

thisis for a 71 with a 390 or 6.4 L. this is a crankshaft kit. it shows several part numbers under the part. http://www.autozone.com/N,15100229/shop ... ultSet.htm i use autozone for quick parts look ups. thats why the link is what it is. because it is quick. that didnt work sorry. if you look it up it will show you the part numbers under the picutre for the crank.

[jay1213]

The connecting rods are the same correct???

[fordman]

no they are shorter i think for a 390.

[jay1213]

All my research indicates that they are the same pistons and rods, the only difference is crank, if anybody could shed some definative light on the subject would b appreciated

[FORDification]

The overall length of the piston/rod on a 360 is longer than on a 390...the 360 pistons would stick out of the block if you just swapped in the 390 crankshaft. You can use the 360 pistons OR the 360 rods in a 390, but not both. (That's how 360's were built...using the 390 piston. The compression height of the 390 4V pistons with the long 352 rods and 3.50 stroke crank made 8.2:1, 390's used the 410 4V pistons to bring it down to 8.4:1.) The compression height of the 360 pistons is 1.776", which makes the perfect 390 piston. The 360 long rod is .052" longer than the 390 short rod, which combined with 1.680" compression height 390 truck pistons would also give good compression. However, the 360 rods are somewhat weaker than the 390 rods.

Incidentally, factory 360 pistons have '390 4V' cast into them.

[jay1213]

So to sum it up, 390 crank and connecting rods is all that's needed??

[sideoilerfe]

and pistons. the compression height is different and the stock 360 pistons have a full skirt as the 390 pistons do not.

[jay1213]

I know the height is different, but it should be fine correct???

[DuckRyder]

It should be fine with a 390 crank, rods and pistons.

If your 360 has the full skirt pistons, I think you will find that they hit the crank. If they are marked 390 as outlined by Keith you can use them. However they are not horrobly expensive so in this case "can" does not neccecarily equal "should".

[sideoilerfe]

If your 360 has the full skirt pistons, I think you will find that they hit the crank.

They would hit the 390 crank but they're stock in a 360.

[DuckRyder]

If your 360 has the full skirt pistons, I think you will find that they hit the crank.

They would hit the 390 crank but they're stock in a 360.

Thanks for clarifying, that is what I meant they will hit the 390 crank.

[sideoilerfe]

If your 360 has the full skirt pistons, I think you will find that they hit the crank.

They would hit the 390 crank but they're stock in a 360.

Thanks for clarifying, that is what I meant they will hit the 390 crank.

I knew what you meant but I just wanted to clarify for Jay1213.