390 Made Into 428

[TMAN0950]

I HAVE BEEN TOLD THAT I COULD PUT A 428 CRANK INTO MY 390 AND IT WOULD BORE TO A 428. IS THIS TRUE AND WILL IT RUN COOL BEING BORED THAT FAR. I AM NEW TO THIS SO THANKS FOR THE HELP TMAN0950

[SFfiredog]

TMan,
There are certain, I repeat CERTAIN 390 blocks that can be safely bored to standard (4.13) 428 size. There is a method of sizing drill bits between the cylinder walls inside the freeze plug holes that will provide you with block candidates to have sonic checked. The drill bit method is outlined on the FE Fourm. Do a search on that fourm. No matter what 390 block you choose to bore out it is STRONGLY recomended to have a sonic map of the cylinder walls performed. Everything else about the swap is a bolt in.
--Mike

[Sizzler]

Originally posted by SFfiredog


TMan,
There are certain, I repeat CERTAIN 390 blocks that can be safely bored to standard (4.13) 428 size. There is a method of sizing drill bits between the cylinder walls inside the freeze plug holes that will provide you with block candidates to have sonic checked. The drill bit method is outlined on the FE Fourm. Do a search on that fourm. No matter what 390 block you choose to bore out it is STRONGLY recomended to have a sonic map of the cylinder walls performed. Everything else about the swap is a bolt in.
--Mike

Well....
the 428 is usually externally balanced, but other than that it's all a bolt in.

But, you don't have to go out to the 428 bore to use the crank. And the longer stroke crank in a 390's bore, or even a 390+ bore is still a good thing. You don't say what use you're planning for this engine. You may find that once you swap cranks, you'll want new rods, then new pistons, and once you go to new pistons the actual final bore size becomes a seriously moot point. Do the sonic check on any 30+ year-old block. Then plan out your build taking into account your expected goals for the motor.

Good Luck

[TMAN0950]

THANKS GUYS, IT DOES NOT SOUND TO GOOD TO PUNCH OUT THE 390 TO 428. TODAY I TALKED TO A GUY THAT HAS A 428 BLOCK NEVER BORED AND A 428 CRANK AND RODS ALL STANDARD BUT HE DOESN'T KNOW HOW MUCH TO ASK FOR IT. WHAT DO YOU THING IS A FAIR PRICE. I WANT A ENGINE FOR MY ERA COBRA. THANKS TMAN0950

[FFR428]

Depends on what block he has STD 428, PI or CJ. Crank and rods also. Ballpark...STD 428 block $300-$500. PI or CJ block $500-$800. Crank and rods STD and PI $200-$400. CJ $300-$600+. Get some casting #''s off the block, crank and rods and post what they are so we can give you a better idea. But this are prices I've seen. some higher some lower. Depends on what you have, how bad you want it. how bad they want to sell it. G.

[CJ428CJ]

TMAN,

I had to shop around a bit but eventually found a complete running 428 out of a 66 galaxy. I got it for $1000. It was un-rebuilt and complete from pulley to flywheel and oil pan to air cleaner.

Chris