Well good news about my crank, I found the casting and it is in fact a 390. Now I have another question. is there a way that I will be able to tell what compression ratio this engine will have?? I bought the engine dissassembled and I have all of the parts setting in my garage. is there a way to tell by looking at the pistons?? or any other parts.
I believe the engine is between a 66'-70'
The guy I bought it from said that it come out of an old sheriffs car.
The engine has a stock 4bbl intake
high performance heads
adjustable rockers
and high performance rods
any help will be apreciated.

 

If it’s an original 390 PI, the CR was 10.1:1. The cam was solid, what kind of lifters do you have?

http://www.fomoco.com/index.asp?Dept=Resources&Tool=Textbook&Eng=25

Mr. F is pretty thorough in making sure his specs. are accurate.
Post some numbers from the block, heads, intake, exhaust, rods, heck even the dizzy.

Barry

 

It's my experience that the advertised compression ratio is not actual compression ratio. Of the 390 and 428 heads I've CC'ed none were close to the volume given in the book and after a valve job they were further off. My first '66 428 was advertised at 10.5 and measured 9:25. Surfaced the block and the heads to get the deck height and compression ratio to meet specs.

Others may have had different experinces ...

Bob
'66 7 Litre, top loader, 3.25 Traction-lock, Sidewinder Intake, SCJ Exhaust
'88 F150 XLT Lariat, 302, 5 speed, 3.08
'99 Ranger, 3.0, 5 speed, 3.73 posi

 

Good point Bob, the FE heads that I've cc'ed were always on the high limit of the spec. or ever farther. I think we’re just talking claimed spec. vs. real-world numbers. Maybe that’s why some of these engines seemed a little overrated by the seat-of-the-pants method.

Does your 428 crank have a 1U on the #7 counterweight? Is there anything on the first counterweight?

Thanks!
Barry

 

Good to see that some one else has had the same experince. Getting them on spec with headers wakes them up whether your towing or racing.

Re the 428 crank: It has been rebalanced twice by me, once as a 428 and again when i built my Dad's '76 360 truck engine into a 410. There are no casting marks left except for an underlined 6 on the first weight that I can read tonight. But several of the counter weights have either been welded on or had extra holes drilled. The #7 counter weight appears stock and has no casting marks.

Did you know that the '66 and '67 cranks have an extra counter weight just before the #3 main bearing? I don't believe this extra counter weight is on the later 428 cranks. These engines use the normal 390 front balancer/spacer.

Bob
'66 7 Litre, top loader, 3.25 Traction-lock, Sidewinder Intake, SCJ Exhaust
'88 F150 XLT Lariat, 302, 5 speed, 3.08
'99 Ranger, 3.0, 5 speed, 3.73 posi

 

You really need to measure things first. There are some calculators out on the web for this, but you need to know the cc's of the head, piston valve cuts, piston to deck distance... You can take the rings off one piston, install it and check the piston top to block deck distance. If the pistons are flat top with 4 small valve cuts, it's probably in the 5.5 cc range and most head gaskets are in the 10cc range, the heads are listed in some books based on casting numbers or you can get some flat plastic and minerial spirits to measure them.

 

I use alcohol when CCing with a bit of food coloring so I can see it. Alcohol evaporates and leaves no mess.

Bob
'66 7 Litre, top loader, 3.25 Traction-lock, Sidewinder Intake, SCJ Exhaust
'88 F150 XLT Lariat, 302, 5 speed, 3.08
'99 Ranger, 3.0, 5 speed, 3.73 posi

 

Bob, I use alcohol when CCing but it never makes it to the head (well, maybe an hour later).

About the cranks, yes I have noticed that extra weight too. It’s not a large as the other ones though. I’ve seen them on 410 and 428 cranks marked with a 1U. Used to think they were all like that. Don’t know the story behind it, maybe DF here has the low down. Thanks for the info, trying to trace the lineage of all these cranks.

Barry

 

I believe the extra counter weight was used in lieu of placing all of the balance weight on the flywheel. The later cranks ('68 and up) deleted this weight and used a special pulley and balancer combination. The newer setup was cheaper to make I guess; certainly the crank was closer to the regular 390-427 ones.

One guy I knew in Albuquerque in 1971 wanted to use the older crank, newer balancer with a 390 aluminum flywheel. I left town before it was done so I don't know how it came out. I would want to lay both out and see where the extra weight lined up. It could work but then again it might not.

You really ought to try using alcohol instead of mineral spirits for the fluid when CCing. It makes the job much easier and leaves the heads clean and dry; paint goes right on without washing the heads.

Bob
'66 7 Litre, top loader, 3.25 Traction-lock, Sidewinder Intake, SCJ Exhaust
'88 F150 XLT Lariat, 302, 5 speed, 3.08
'99 Ranger, 3.0, 5 speed, 3.73 posi

 

Well,........my 1U crank has the funky little weight ahead of the number 3 main. I guess I can still learn 'cause I thought all the 3.98 cranks were that way. DF

 

I did some research last night and I believe the statement about some 428 cranks not having the extra counter weight was incorrect. The guy that going to do that was often blowing smoke and while I saw the crank in the bench it could have been out of a 390 since I didn't look closely at it (and this was thirty years ago). He was a bit of a character and while he had the first set of aluminum head big block heads I ever saw, he ran some weird things like a aluminum case T-10 behind a built 427 because it saved weight. Of course the case split apart a couple of times a year.

I think that the small balancer weight would not have worked as he planned. The flywheel imbalance is quite a ways out from the flywheel flange and the small balancer is very close the crank so they would have very different effects on the engine balance.

What I have been referring to as the small balancer is Crankshaft Spacer C9ZZ-6359-A and is described as having a counter weight.

There are also two Crankshaft Vibration Dampers, C8AZ-6316-B or C. "B" was on the "standard" 428 and "C" on the CJ. I believe "C" was used on the SCJ as well.

The only reference to the early 428 crank I can find is on page 42 of the August 1967 issue of Hot Rod. While the article mistakenly assumes the 352 and 390 engines have the same bore, it does state that the pistons, crank and flywheel are the only pieces necessary to upgrade a 390 into a 428.

On page 54 of the Muscle Parts book by Ford (published in late 1969 I think) there is a sidebar on the lower right that lists four different cranks and pistons for the CJ and SCJ 428s. Basically they were early and late versions of each with the later pistons stronger and heavier. The CJ engines used 427 rods as well as heavier pistons and it was probably more cost effective to use the small balancer than cast a new crank.

Page 52 of HP Books "How to Build Your Big Block Ford" by Steve Christ lists five 428 cranks.

Other books duplicate the data given above.

I can scan any or of all of these references and e-mail them to anyone who sends me their e-mail address. Mine is bsprowl at bellsouth.net .

I hope this clears up what I think is an error in my earlier post.

Bob
'66 7 Litre, top loader, 3.25 Traction-lock, Sidewinder Intake, SCJ Exhaust
'88 F150 XLT Lariat, 302, 5 speed, 3.08
'99 Ranger, 3.0, 5 speed, 3.73 posi

 

I'd like to get to the bottom of this too. That extra weight in front of #3 was an easy way to quickly ID a 428 crank. There have been a couple of early 428 cranks on eBay and the seller made a special point about the weight being there. I thought they were all like that. If you guys come across any post '68 cranks of any flavor, could you make a mental note about the weight? Thanks!
Barry

 

Bob, you were right all along about that extra counterweight! Confirmed it via a forum search.

Don't second-guess what you know, it's usually right!

Barry

 

Thanks, Barry. Like I said the guy blew a lot of smoke and it was thirty years ago.

And I was wrong about the end carb idle circuits in the tri-power setup that is being discussed in another thread.

Why don't we ask Ken to add an a section to the FAQs that cover things like this. I see the same questions about towing capacity, transmission gear ratios, differential gear ratios (which are in the owners manual at least for my '99 and '88), engine bell housing groups, etc.

I would be please to write some of these and I suggest that Ken ask several someone people in each area to review what I (and others, I can't address some things) have written. When we get agreement that the answer is accurate, it can be added to the FAQs.

I hate reinventing the wheel and arguing about facts.

Bob
'66 7 Litre, top loader, 3.25 Traction-lock, Sidewinder Intake, SCJ Exhaust
'88 F150 LWB 4x2, XLT Lariat, 302, 5 speed, 3.08
'99 Ranger, 4x2, 3.0, 5 speed, 3.73 posi