428 crank

[FirstEliminator]

   Hey guys,

    My 68 Colony Park is a 428 car. The flex plate is missing a tooth so I pulled the trans. Of course I had to open to trans and found 3 clutch- drums for both forward and direct. I upgraded to fit 4 clutches in each pack. Plus put in a wide band. also, I put in E4OD front plant to make the C-6 wide ratio.

    Anyway, I was just getting ready to put the new flex plate on and noticed it has a balance weight. So, my question is:  Are all 428 externally balanced? Or, is it only the 428 CJ?

   If all 428 are external balanced, I have the feeling someone robbed the 428 and put in a 390 sometime in the past.

   Since it was obviously running without vibration using a neutral balance flexplate, I am going to take one off my 390 that's on a stand to get this together tonight.

    It will be disheartening to find that might not be a 428.

   Thanks,
      Mark

   

[ScotiaFE]

You can always do a stroke check.
A small stick/rod down the spark plug hole to measure at TDC and BDC
and anything close to 4" is your 428 and close to 3 3/4" is 390.

[jayb]

All 428s are externally balanced.  However, if they have been rebuilt at some point, Mallory metal could have been added to the crank to make the external balancing unnecessary.  Check the stroke like Howie says and you will find out what you've got.  If it is a 428, and it was running without any vibration with the neutral balance flywheel, I'd put a neutral balance flywheel back on.

[FirstEliminator]

    That just about guarantees that it's not a 428.  Someday I will check the stroke to verify. At this point I suppose it doesn't matter. Just another aspect of getting F'd when buying an old car.

 
    thanks for the info,
        Mark

[jayb]

Mark, I would really think about checking the stroke with a welding rod or dowel down the spark plug hole before getting a new engine.  It is possible that the engine is still a 428, and someone put on a 390 flywheel.  If you don't run the engine at high RPM, its probably not going to vibrate with that 390 flywheel.  The only way to know for sure is to check the stroke - Jay

[Barry_R]

I've done that test on the dyno (not on purpose... ) and they shake pretty good....

[Joe-JDC]

Believe me, a stock 428 engine WILL shake with a 390 flexplate installed!  I have experienced it, and it is unmistakable.  It starts almost off idle and just gets worse the more rpm you go.  You either have a different shortblock, or it has been neutral balanced like Jay said.  Joe-JDC

[jayb]

Thanks for the info guys, I guess I'm surprised they shake at lower RPM - Jay

[thatdarncat]

Mark, When you had the flexplate off did you happen to notice if the back of the block had a "scratch" mark? Usually an "A" or "C" on most 428's. Have you looked at the date code on the block? If the engine was replaced it may not be a date that makes sense for the production of the car. In '68 ( and later ) most engines received a partial VIN stamped on either the back of the block or on one of the cylinder heads. It may not be easily visible but worth a look if you still have the transmission out and can look through the transmission tunnel, might help determine if you still have the original engine.

[FirstEliminator]

   The date code was pretty rough to read. It did start with a 6. So we know the engine has been replaced at some point in the life of the car with an engine that is a couple years earlier. Probably a 390. Could be a 410 or a 352.

  I don't recall seeing any particular markings on the rear of the crank.

   The trans is in and I drove the car last night.

     I'll accumulate a 428 to make things right. Eventually this car will be getting a full restoration. It's a pretty well optioned car and quite deserving of preservation.

   thanks,
    Mark

[turbohunter]

Kevin was talking about the back of the block itself Mark.
If it had a mark like this (or an A, could be unreadable also) then you would prolly have a 428.



I have a good friend that just bought a Q wagon and found it was a 390 replacement.

[57 lima bean]

"Could be a 410 or a 352"...These have different flex plates.The 410 would have the external weight as the 428.

[FirstEliminator]

   I was noticing the back of the block had paint on it. I didn't notice anything that looked like that deflated C.

   410 has external balance?---well, 352 or 390-----probably a 390.

[FirstEliminator]

   Hey guys,

   So I've been looking around for a 428. The other night I had put an ad on Craigslist for WTB: Ford 428.  I walked into work this morning to find a message on my answering machine that a guy had a 428. Surprisingly, he only lives 2 towns away. The heads are still on the engine. So I can't measure the bore. I know to look for the external balance weight---but it could still be a 410.  What are the defining features to tell the difference between a 428 and a 410?

   thanks,
     Mark

[thatdarncat]

It sure would have been nice if Ford would have just cast a big "428" on the outside of the block, but they didn't. My first bit of advice would be to check out 428cobrajet.org - best place by far for info on these motors. Here's a link right to the engine block I.D. section, but the whole site is a good read.

http://www.428cobrajet.org/id-block

It's pretty much impossible to I.D. a 428 from the side or front of the block, best clue is either the "A" or "C" scratch mark on the back of the block like the picture Marc posted. Since the 410 is just a 390 block with the 428 crank they most likely won't have a "A" or "C" scratch mark. If the seller will remove the core plugs you MIGHT find a cast "428" on the bottom of the water jacket, but it could be on one side and not on the other, or could be in the front or rear ( only visible with a head off ). One of those newfangled video bore scopes could be helpful.