360 to 390
New User
Joined: Sep 2003
Posts: 2
Likes: 0
From: Great Falls USA
360 to 390
Just the Crank and rods. a 360 is a 390 block with a 352 stroke. So the bore is already right, no need for pistons.
Nick Sand
1971 & 1967 F100 390 C6
if you are looking for ANY parts, E-mail me.
Nick Sand
1971 & 1967 F100 390 C6
if you are looking for ANY parts, E-mail me.
Post Fiend
Joined: Jun 2003
Posts: 8,209
Likes: 12
From: Black Hills of SD
360 to 390
Ok so you are saying then that the deck height is the same on both the 360 and 390 pistons? Then the rod length is all that is different? I had actually never done this and told someone that the pistons were different and the rods were the same. oops!
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Post Fiend
Joined: Jan 2003
Posts: 8,600
Likes: 4
From: Iowa
360 to 390
No, the compression height of 360 and 390 pistons are different. 360 pistons have a compression height of 1.776, and 390 pistons have a compression height of 1.680. If you use 360 pistons in a 390 you should have .016 deck clearance, so it should work. The only thing is, some 360s were built with 390 pistons from the factory, so the only way to know which ones you have is to measure them. In any case, if you have the slipperier skirt pistons, as opposed to the full skirt pistons, they should work. Just 360 pistons will develop more compression than the 390 pistons.
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Post Fiend
Joined: Jun 2003
Posts: 8,209
Likes: 12
From: Black Hills of SD
360 to 390
Thanks rusty. I don't know the formula but it seems that .96 would be a lot more compression. A reconditioned rod would take care of a little bit of it. Of course the whole point is a bit lost when you consider that most engines that are apart probably need rebuild and bored out which would required new pistons anyway.
Are there aftermarket pistons that allow you to use the 360 rods on the 390 crank? It seems like that would make the swap a little cheaper.
Also I would offer this bit of advice. Try to get the earlier block. The last 2 or 3 years of the FE they had too many reliability problems which seemed to be related to the alloy in the block and heads.
Are there aftermarket pistons that allow you to use the 360 rods on the 390 crank? It seems like that would make the swap a little cheaper.
Also I would offer this bit of advice. Try to get the earlier block. The last 2 or 3 years of the FE they had too many reliability problems which seemed to be related to the alloy in the block and heads.
Logistics Pro
Joined: Oct 2000
Posts: 3,960
Likes: 5
From: All over Texas
360 to 390
Are there aftermarket pistons that allow you to use the 360 rods on the 390 crank? It seems like that would make the swap a little cheaper.
I've heard that one can use the longer rods without problems (except a higher CR), however, they are not nearly as "beefy" as the 390, 428, 410, etc. rods so by trying to save $50, you'll be handicapping your engine.
Post Fiend
Joined: Feb 2001
Posts: 6,624
Likes: 8
From: Missouri
Exactly. I used a 390 crank, rods and TRW L2291F60 pistons on my conversion. The 360 rods are a waste. You are only going from a 1.71 rod/stroke ratio to a 1.73 ratio. You won't see that difference on the dyno no matter how hard you look. The 390 rod is much beefier. The blocks are 100% identical.