Okay, I know this question has been asked time and time again but I'm going to ask again, how hard is it to turn a 390 into a 427???? is it simple like heads, cylinder bore, etc... or is it more complex than that?

 

You really cant becasue the block was cast with different cylinders so i dont think you can bore it out that much it would be catastrophic. but the guru's will know.

 

Correct. The only thing that would be required to turn a 390 into a 427 would be to bore the block to 4.23 and buy 427 pistons. Easy as that. 'Cept you cant bore a 390 or 428 to a bore of 4.23 without seeing the water through the cylinder walls.

Keep thinking though. That's some of the fun of the FE family, much interchanging can be done.

-Scouder

 

you can always drop 5grand for a gensis block. and then go from there!

 

I suppose you could bore the cylinder bores out of the block and have new 4.23" ID sleeves put in. That way you'd have a 427 top oiler, kind of.

Probably easiest to buy a new genesis block.

Why do you need a 427? Keith Craft has ported Edelbrock heads for a 390 that flow, like, yeah.

 

I may be way off the track here but I read somewere in a Ford book that the very first FE blocks from 58 I think? were able to be taken to 425ci's Maybe if some one around here remembers 1958 they could correct me here

 

I wasn't dead set on turning this engine into a 427, just wanted to know if possable, how big can you make an FE motor before you jeprodize the opperation? Or what's the most common build up for these motors?

 

you could make it a 428

 

The most common buildup by far is the 390. Most start life as 360's. Then you get 390 crank and rods, use the 360 pistons, and viola, you've got a 390 with decent compression.

 

A 416cid (4.08"x3.98") is the safe limit for a 390 block. This is done by boring it 0.030" over and installing a 428 crank with custom pistons. I don't know the proper compression height off the top of my head. Some 390 can take a 428 (4.13") bore. You need to get the block sonic tested before you try to do this. If you bore it 0.060" over with the 428 crank you will get 422cid. This may cause overheating issues.

 

Is the only difference between the 360 & 390 pistons the compression ratios, and then different chamber sizes (if that makes sence).

 

crank stroke is 3.78 on a 390 and 3.50 on a 360.

 

The differences are pistons, rods, and crank. However, 360 pistons, when used with 390 rods and crank, do work and give better compression than the 390 pistons, which have a lower compression height. The crank differences are as noted above.

The earlier years 390's had the same pistons as 360's for more compression. However, Ford used their surplus 410 pistons in the 390's to lower compression in later years.

 

Sorry, I should have been a little clearer, I meant in the top end, I knew about the bottom end, my fault.