Happy Monday!!

I was having a discussion with a guy I work with about the 390 truck motors in the 70's F150 and the 390 in the mid to late 60 Fairlane, Galaxie & Mustangs. He was thinking about swapping the two thinking the truck motor was an inferior casting. Low compression under powered, from what I can tell the only difference is the pistons and the cam. Would I be correct here? I hope I am correct because he hates to be wrong especially after he spends the money and finds out he didn't have to.

Thanks for any help.

 

Truck Pistons do sit considerably down in the hole compared to car. I can't remember how much exactly but I want to say it was something like .100. Other than that I'd rather have a later truck casting. Last one I got was a 360 with the mirrror 105 casting.

 

Agree with PA even though I know nothing about the 390 castings themselves.
Just that Ford typically improved the block castings of all their engine families as time went by.

Yes, there were earlier engines with more compression, and sometimes the high-po cars got more cam, bigger exhaust, different carbs, or whatever it took to get that 10hp to 50hp bump they were looking for. So the cars almost always got the big numbers.
But the trucks usually got the bigger stuff where needed. Like metallurgical mixes, thickness changes, bigger bearings even in some cases (though I don't think the 390 got that kind of a change?) so I don't think your friend is going to see any improvement going backwards in time.

Although he could pay more money. Collectors usually drive muscle-car era stuff higher in the price ranges. So he might lose in the bang-for-the-buck category at any rate.

Like I said though, I don't know any of that stuff about 390s/FE's specifically. Just that what I said has been kind of a trend in the other engine families I know of.
Of course, then there's the Australian-made, and Mexican-made engine blocks with their supposedly higher content of certain metals that were seen to be improvements. Only in some engine families though, but it still muddies up the mix!

Hope he finds a good happy medium no matter what he does. Happy is happy, even if you take a different route.

Paul

 

360/390 share the same block, the bore is the same (4.05"), the stroke is different.

Early 360/390 block has 352 cast on it. Circa 1971/72, 352 was replaced by reversed cast 105.

Hardened valve seats introduced in 1972, head casting number: D2TE-AA

 

You might refer your friend to Barry Robotnick's book "How to Build Max Performance FE Engines. DIY Ford offers excerpts from this book on-line that you can read for free, see: https://www.diyford.com/category/for...x-performance/
In particular:
Ford FE Engine Block: The Complete Guide
How to Choose Ford FE Engine Factory Cylinder Heads

 

Thanks or the responses, all good info. I will pass it on to him.

 

Be careful when selecting a good candidate regardless of what year casting you get. Fe blocks are very thin on the outside by the freeze plugs. They can crack without pushing the plug out if left with water in them.

A number a years ago when I got my grandpas truck back from the guy he sold it to it was broke. When we drilled the block to fix it I couldn't believe how thin they can be.