Hi, I am planning on rebuilding my 360 and adding a 390 crank and rods. Where can I buy a crank and rods resonably and what rebuild kit would you guys recommend? Thanks Andrew

 

Good Morn'un!

I picked mine up from the local Craigslist web-site.

Another option would be your local salvage yard. You might be able to pick up the parts there for cheap...... even the whole engine.

If you do pick up the entire engine I recommend that you measure the stroke and insure that it is truly a 390. You'd be amazed how many 390's sold are actually 360's. Stroke should be 3.78" for the 390 as opposed to 3.5" for a 360. Even better, if the engine is out pull the pan and verify the Crank shaft numbers.

Lee

 

I found someone selling a 390 crank and rods locally so I might pick those up. What do you guys recommend for pistons for a 390 with headers, 4 barrel intake, cam and holly 650?

 

Are you going to tow and haul at max weights? Or is this a light duty driver?
If it's a light weight runner, use the late '60s "Regular Fuel" 390 piston. It is also used in the 360 pickup engine. It has four valve reliefs and a slight dish and willl give you about 9.5 CR, depending on your heads.

As OEM, Ford used the 410 spec piston in the 390. This resulted in the piston being down the hole about .100, with resulting low 8 compression. This is a power and economy killer, but if you are going to haul heavy, you need to go this route or you will risk heat, detonation, and piston hole issues.

 

85e150six4mtod gives great advice

Because I tow a 7500lb travel trailer regularly over a 6000ft moutain pass, I went the conservative route for pistons. I use Silv-O-lite 1130's.

Using Mr Gasket #1132 .020 steel head gaskets yields ~9.25:1 CR.

Unfortunatly for me, after 100 miles I had anti-freeze in my oil with the thin steel gaskets so I switched to FelPro .041 composite head gaskets. Due to their thickness CR went down to ~8.79:1.

For me this is not to much of an issue as I can pull the heavy RV over the mountain on 87 octane gas with no pinging

Lee

 

The 1130 is the piston I am talking about above. Nominally 9.5, your final CR depends on combustion chamber volume, any head or block resurfacing and the gasket. Calculate in advance, measure twice etc and rebuild your motor once.

 

That is good news because I will be able to buy a 390 crank and rods and put them in my 360 with my stock 360 pistons.

 

That will work as long as your stockers are in good condition and still within spec. Some 360s got flat top pistons, as used in the "Premium Fuel" 4bbl car 390 motors. (and Mecury "Premium Fuel" 2bbl motors). So beware of those, as you may end up with higher compression than you want. Those were nominally 10.5:1.