Hello
I am wondering how thin the cylinder walls can be before you need to worry about problems. We are boring a 352 to a 390 and would have about .100 wall thickness. Is this too thin. Will it cause too much heat and crack due to this thickness... I am having trouble finding a 390 block with a date code of C6 or C7 if someone has one to get rid of let me know please. This 352 is all I can come up with... Is it advisable to even use it.. Thanks Again..

 

Why not find a 360 all it is a Destroked 390 i have seen a few 360's and 390's on Ebay.

 

Both the 360 and 390 are based on the 352 block, so boring a 352 to 390 shouldn't be a problem. If I recall...boring .060 will change your cylinders to 390 specs.
You'll also need a 390 crank and rods.

 

Look in the later model Trucks with Fe's in the for a D2,D4TE block...They should be able to be had for next to nothing.. Those are the 360/390 later blocks... JMO..

and on any over bore you dont want to go any thinner than about .100" on the non thrust side walls.. and you wont know that without a sonic check..and thats money toward a block that will have a thicker cylinder.. JMO...

RJ

 

360/390 blocks are common as dirt. I've got two left of several I collected in a few years time. Seems everyone want em, but doesn't want to pay the freight to get em.

 

At .1" it's still ok, but that will be the block's last overbore.

 

Why not just build a 380? 352 bore, 390 stroke. Will look like either on the outside and you don't have to worry about overboring too much. . .

Justin

 

A 352 has a 4.00" bore and a 360 or 390 has a 4.05" bore. so the over boare is .050".

 

I would look for a 360/390 block first, they are dime a dozen in the right places. Last resort should be boring a 352 out that .050 to the 390 bore (which should not be a problem, I almost did that once) As you may have already read on here, the D2TE and later blocks, that have the mirror 105 on the front are the easiest ones to find, and they are s'posed to be stronger (I can't imagine that the difference is enough to matter though..LOL)

 

I would just bore that 352 block .050 over. It will be easier than getting a greasy old block, hauling and having it rebored also.

 

I'm curious, if these 360/390 are a dime dozen, what are people willing to pay for one? I wouldn't ley one go for under a $100 myself.

 

That's because you are an FE addict and your view of reality is badly bent.

 

Depends on if the guy knows what he has and how badly you want the motor. Most recent 390 I picked up was a about 5,000 mile rebuild complete.pan to carb, fan to flywheel built to tri-power specs (but with a single 750 4bbl).

I acted like i didn't really want it and he really wanted it gone. Wound up giving $100 for it because the guy wanted it out of his garage since he hadn't talked to the guy that was storing it there for 3 years. And from what it does in my thunderbird, heck yes it has 400hp

Justin

 

I've paid $50 for the 2 I've gotten, but one had a gouge on the cylinder wall from the wrist pin sliding against (hence getting 2 of them )....I'm about to get another this weekend, will probly pay $50 for this one too!

 

I've got a good low mileage 60 over 390 with a C7ME-A block, C4AE-B crank and C7AE rods and nobody's willing to pay $350 for it plus shipping. Also got a std bore C4AE 390 block with thick walls, and the cross bolt knorbs, both sides and it's the same story on it, $350 + shipping--no takers. Guess I'll just put em in storage for another ten or so years and see what's what then