Why did Ford change the small block offset balance?

[machoneman]

Mustangtek doesn't really go into structural differences year-to-year. I was wondering why you used 1969 as a cutoff, as '68's should be identical. The story is that the bore length was slightly shorter on the 289 blocks, but otherwise same same.

Bottom line is I have about 20 '64-'71 engines, in and out of cars, about an even split between 289's and 302's. If the blocks are worth more than later roller castings, then how would I go about selling them for the extra bucks? Bare, built short blocks, complete?

What would be the best SBF forum these days?

No, they don't go into detail as do most any other site. Many engines installed in 1969 cars were actually cast in late 1968 by casting I.d. number (model year versus actual casting date). And yes, wall length does count for stroker applications. And I never mentioned value as that's up to the seller and buyer.

Nope, nothing worthwhile on a pure SBF engine site. Good stuff on car related (i.e. Cobra, Shelby) sites.

Never recommend any and won't. Kinda' like sending your pals to your fav restaurant and then they have a sucky meal!     

[gt350hr]

     Heo,
       The last 289 hi po "service" short blocks Ford sold were in fact the Mexican block ,289 crank, Boss rods, and cast pistons. A friend of mine bought one from the local dealer and was surprised when he went to use it and found the block and rods. The "myth" about the block being superior has been around for over 40 years and is NOT true. The caps are thick like a HiPo and that is it.
    Randy

[Falcon67]

I also recall some late or middle 68 289 production used the new 302 blocks.  I've had several emails over the years with pics of the 302 in the valley with the question "I thought it was a 289?". 

I have a 72 351W block with .020 over bores (needs touch up) saved in the shed.  I can pick up a 351C block, not far but a little.  I can't pick up the 351W block.  They are technically not supposed to be that much different but the double arm lift with your legs test says they are by a bit at least. 

LOL, file the Mexican block thing with all the "high nickel block" deals. 

[machoneman]

I also recall some late or middle 68 289 production used the new 302 blocks.  I've had several emails over the years with pics of the 302 in the valley with the question "I thought it was a 289?". 

I have a 72 351W block with .020 over bores (needs touch up) saved in the shed.  I can pick up a 351C block, not far but a little.  I can't pick up the 351W block.  They are technically not supposed to be that much different but the double arm lift with your legs test says they are by a bit at least. 

LOL, file the Mexican block thing with all the "high nickel block" deals.

Yeah, the 351C block (and engine design) was a great one save for thin bores. Had too many where at a .030 bore one could push a sharp ice pick right through some weird, dark looking areas on the lower cylinder walls, especially #5. I surmised long ago in casting, the oil filter mount somehow pulled away the poured cast iron, leaving the non-thrust walls on #5 really thin. The 351C Pro racers of the era did all pretty much have all eight sleeved, a big expense even back then. Too bad Ford never cast up a batch of much heavier-walled blocks for the racer set....they never did. 

[gt350hr]

  Bob ,
    Ford did in fact make some "good" 351C blocks for racers using SK numbers. The "366" blocks had 4.080 bores and were used in Nascar only. The last "good ones" were made in Australia ( all the patterns went there) at the Gelong foundry. The "good ones" have an SK or XE number instead of the normal DOAE  or D2AE casting number. "Production" blocks as you mentioned were horrible for core shift on #5 cyl. Yes THE BEST blocks were the "furnace brazed" as you noted.
   Randy

[machoneman]

  Bob ,
    Ford did in fact make some "good" 351C blocks for racers using SK numbers. The "366" blocks had 4.080 bores and were used in Nascar only. The last "good ones" were made in Australia ( all the patterns went there) at the Gelong foundry. The "good ones" have an SK or XE number instead of the normal DOAE  or D2AE casting number. "Production" blocks as you mentioned were horrible for core shift on #5 cyl. Yes THE BEST blocks were the "furnace brazed" as you noted.
   Randy
[/quote

Randy you are correct and yes, that I knew plus the Aussie connection. 

But, only factory sponsored NASCAR teams here in the USA got them or race major teams (read: long-time drag racing teams like Nicholson , Schartman, et al. Heck,even some nascent Can-Am and FIA teams got a few) that had a pipeline for those special blocks. The 351C runners in drag racing at least knew Ford only make a handful of these non-production blocks and I was told even they were used up damned quick as so many (in drag racing only) had to revert to furnace-brazed sleeves to OEM 351C blocks near the end of the less-than-500 CID Pro Stock era.

We knew a few of those 351C Pro Stock runners then here in the Midwest and the had those highly prized those blocks which btw they could hardly give away (Hi-Ported steel heads, complete engines, etc.) once the NHRA switched to the 500 CID rule. Had offers to buy complete or parted-out 750hp or so Pro engines for a song then but I didn't bite as we had all our bucks in Boss 302 engines.   

Yeah, what I should have said was the for mere mortals, a thick-walled OEM block available to all would have helped immensely to slay all those Chevys.  Imagine too a world-beater tall deck 400 CID stock thick-bore bore Cleveland engine that coudl easily go to 454 CID or so. Killer!   

[gt350hr]

    Ford at that time was desperate to make quality blocks. I have at least 7 different SK numbers for 351C blocks ( revisions) They tried "square" casting cores for the cylinders and multiple changes to the round cores . They tried slowing down the flow rate of the molten iron in order to stop "moving" the cores around during casting. The scrap rate on Cleveland blocks was the highest in Ford's history.
    Randy

[babybolt]

Only the first year or two of the Mexican block had "normal" 302 hardness in the iron, after that those blocks used soft junkier iron, must have been remelted SBC's.  You can see it in the bore wear, most the Mexican blocks worn out and needed at least 0.040" to clean them up way back in the day.

Then Ford made some 302 Versailles blocks with the HD caps around 1976.

After 1985, around 5 lbs or more was added to the 5.0L block, not sure if this happened in 86 or 87.  5.0L blocks have a bad tendency to crack outward from the front left #5 head bolt hole.  351W roller blocks have cracked in the lifter gallery.  Both 5.0L and 351W roller blocks are harder than previous blocks and usually don't have much bore wear.

A Ford engineer told me that in 1994 Ford built a new machining line for the 302 and 351W and those blocks made off that line have significantly more accurate tolerances.

[machoneman]

    Ford at that time was desperate to make quality blocks. I have at least 7 different SK numbers for 351C blocks ( revisions) They tried "square" casting cores for the cylinders and multiple changes to the round cores . They tried slowing down the flow rate of the molten iron in order to stop "moving" the cores around during casting. The scrap rate on Cleveland blocks was the highest in Ford's history.
    Randy

I had heard that (lots of revisions). Very strange though that Ford kept demanding (they must have) that even those special 351C blocks had to have water jackets between the cylinders! Heck, today one can even buy siamesed Windsor-based SBF's right from Ford! I guess they were trying to appease all the potential users where a NASCAR/FIA sports engine I guess they figured had to have full coolant circulation around each cylinder.

[pbf777]

Very strange though that Ford kept demanding (they must have) that even those special 351C blocks had to have water jackets between the cylinders!  I guess they were trying to appease all the potential users where a NASCAR/FIA sports engine I guess they figured had to have full coolant circulation around each cylinder.

     Yes, because when in service, functioning, this results in the most progressive dimensional growth change in response to the heat experienced by the casting throughout the cylinder's circumference.   And ideally one needs the cylinder wall thickness to remain constant about it's circumference also; this was a drawback to the "squared" cylinders as they did/don't remain as round when heated, but perhaps better than the "siamesed"-cylinder block castings.   The siamesed-cylinder casting configuration is such due to no other choice of chosen cylinder bore diameter vs blocks cylinder bore spacing limitations.   

     Scott.