FE 352 block to 390

[DuckRyder]

This topic has been split out of a wanted to buy post...



A 352 block has a smaller bore than a 390. They will not always over bore to standard 390 bore.

[stephen44]

A 352 block has a smaller bore than a 390. They will not always over bore to standard 390 bore.

so i was told that the 4.000 352 bore will always over bore to 4.050 (390) - are you saying this is not the case ?

[DuckRyder]

A 352 block has a smaller bore than a 390. They will not always over bore to standard 390 bore.

So I was told that the 4.000 352 bore will always over bore to 4.050 (390) - are you saying this is not the case ?

Sort of.

I apologize for the brevity of my original reply, I probably should have explained more thoroughly.

I would be very cautious of saying "always" or "never" where Ford blocks in general are concerned and where FE blocks are in particular are concerned.

The general consensus is that .30 over is safe for a high performance build on a Ford block, particular blocks may go more and it depends on the individual block as well as intended use and power levels.

For a mild build to a 390 (I would consider 300-325 out of a 390 mild) there is an extremely high likely hood that the over bore to standard 390 bore will be safe. If your machine shop has the equipment to sonic check it, I personally still would. The more money you plan to spend on parts and the more power you expect to make the more I would want to sonic check it.

[stephen44]

A 352 block has a smaller bore than a 390. They will not always over bore to standard 390 bore.

So I was told that the 4.000 352 bore will always over bore to 4.050 (390) - are you saying this is not the case ?

Sort of.

I apologize for the brevity of my original reply, I probably should have explained more thoroughly.

I would be very cautious of saying "always" or "never" where Ford blocks in general are concerned and where FE blocks are in particular are concerned.

The general consensus is that .30 over is safe for a high performance build on a Ford block, particular blocks may go more and it depends on the individual block as well as intended use and power levels.

For a mild build to a 390 (I would consider 300-325 out of a 390 mild) there is an extremely high likely hood that the over bore to standard 390 bore will be safe. If your machine shop has the equipment to sonic check it, I personally still would. The more money you plan to spend on parts and the more power you expect to make the more I would want to sonic check it.

no that was fine ok - I actually have posted this on another thread about the stoker bores .... aren't a 352 block and a 390 block the same - meaning of i can take a 390 block to + 0.030 why can't i take the 352 block to at least the 390 and even why not to the 390 + 0.030 - again they are the same block

that is one of the many things that confuses me - but i am trying tolearn

[DuckRyder]

They are not the same block.

360/390/410 is the same block

[stephen44]

They are not the same block.

360/390/410 is the same block

but all marked 352

[DuckRyder]

You can find 428's and 427's with that 352 on them, it does not mean anything... well it probably meant something to someone at some point, but to us, it does not mean anything.

FE block casting numbers are for the most part useless, sometimes they might tell you what it isn't, but they rarely if ever tell you with certainty what it IS. To top it all off most of the books have errors in them.

[stephen44]

So we are returning to my best plan is to find a "new to me" 390 block to work on & not to spend the money on the 352 block ?

- Stephen

[mkpj1]

Let's skin this cat differently,

Tell us what the motor is in and preferably the VIN#. Sorry if you already posted this but please for me,..do it again.

[stephen44]

Let's skin this cat differently,

Tell us what the motor is in and preferably the VIN#. Sorry if you already posted this but please for me,..do it again.

the vin says it's a 352 and the tab under the coil says 352. The previous owner says original motor and the stroke measures as a 352.

Cpmpression is 140 on 7 cylinders and 60 on 1 - going up to 135 with oil.

I want to get to 300+ HP for fun and budget matters so it is looking like my best bet is to find an old 390 block and start from there.

[TNIceWolf]

My opinion is that the 352 casting number on the block only refers to a type of casting or block design . Depending on demands for production the castings could be easily changed internally for whatever was needed............and some sand cores could have easily been made ahead for upcoming variants of larger displacement engines or improved performance and used to cast a thinner block design but with thicker walls to prevent production loss. Does that make any sense to anyone? Wouldnt that result in the differences in the wall thickness issue?

[mkpj1]

Well, you didn't post the VIN so I'm going to take your word that you have a 352. In that case you have to read what DR has posted and """that unless you sonic your block you will have no idea whether you can go to a 390 bore safely!""" So,....my suggestion is that you go and find a truck with a "360" and/or get a "360" motor at a junk yard and rebuild it to a 390 which will gain you possibly +400hp at the flywheel if done right. You will still need the "390" crank and rods. Everybody replaces pistons depending on the rebuild so you will have to wait until then to determine the required piston size.

My overall recommendation is that you Google Steve Christ and purchase his book.

Good luck.

Ken

[stephen44]

Well, you didn't post the VIN so I'm going to take your word that you have a 352. In that case you have to read what DR has posted and """that unless you sonic your block you will have no idea whether you can go to a 390 bore safely!""" So,....my suggestion is that you go and find a truck with a "360" and/or get a "360" motor at a junk yard and rebuild it to a 390 which will gain you possibly +400hp at the flywheel if done right. You will still need the "390" crank and rods. Everybody replaces pistons depending on the rebuild so you will have to wait until then to determine the required piston size.

My overall recommendation is that you Google Steve Christ and purchase his book.

Good luck.

Ken

sorry - vin is F10YEA72xxx

yes i have Steve's book

[stephen44]

so it looks like 352 can only be bored out +0.030

so this gives me 357 Cu in

but if i use the 390 crank - the extra stroke gives me - 386 cu in


so the plan..tell me where i go wrong please ..

352 block bored +0.030
390 crank - this is just straight swap right ?
390 rods - stronger than 352 rods ?
390 car pistons +0.030 - these =are high compression right ?
comp cam - suggestions ?
original heads - if budget allows I will get them skimmed and the exhaust ports skimmed.

thought - skimming the head - does that give me clearance problems - will i need to put hardened valve seats in if cleaning heads up. - I might try some DIY porting.

good intake -edelbrock performer or RPM - suggestions
4 barrel 650-700 cfm carb - again suggestions ?
ignition ?

what else - sounds too easy now ?

thanks for all the help and encouragement guys - Stephen

[mkpj1]

Sounds like a good plan. Steve's book is considered the bible.

I came in this without some info you may have put in another post but you must have a 67 F100 with the "Y" 352 for that year. That would make me feel better as that block is probably identical to a 360/390 block of the same era. I would feel safe to bore to 4.05 and get a good 390 crank. May want to go with steel instead of cast if you can find it. The rods are probably the long version and I would try to find the beefier shorter "Lemans" rods. Really should have no clearance issues on the deck but remember to watch your compression numbers when you choose your pistons so you can stay on pump gas. I had to run 2 head gaskets. Try to find some adjustable rockers if you can as well. Have the typical head job done as well. I'm thinking the c8-ha are the best breathers.

Break the engine down and have it cleaned then talk with your machine shop guy. He can do some initial measurements to see where you are with your current block and go from there. DR is right, the only way to be sure is to have it sonic checked but that block should have plenty of room. The early 332/352, not so sure. If the machine shop guy looks at you funny when you ask about a FE,..find someone else.

Have fun!