Service Block

[aero993]

I've seen several people selling 427 SO. Some are advertised as service blocks other have been listed as NOS. What exactly is a service block?

[A Snake]

Somebody with more knowledge than I have, will probably disagree, BUT, "NOS" means "New Old Stock". I have always interpereted "service bock" to be one meant for more than one purpose like a 360/390 service block once was. Now I know that the 427 wasn't offered in different dispalcements, but it could be meant for marine use or other industrial usage besides automobiles. If there are actual differences, I have no idea what they would be. Maybe one of our more knowledgeable FE guys will jump in?

[wtcobra]

A 427 S.O. service block was a replacement block Ford came up with around 1968. It has ribs on the side of block. Easy to see.

wt

[aero993]

Why is it less desirable, people seem to treat it like a stepchild?
What are the purpose of the ribs?

[computerworks]

As I understand it, there could be two reasons:
First, emotional...since it is a replacement part made and sold after the original timespan of Cobra production...hence, less "correct"

Second, technical... since the blocks were made after complete engine production of the 427 was shutdown, there is a higher likelihood of "defective" attributes on service blocks, like core shift when the block was cast.

As stated above...we need to hear from the real FE experts on this...(George?) ...sometimes I tend to swim in hearsay.

[bmalone]

They were drilled for for hydraulics--so you could run either way, solid or hydraulics. I have heard rumor that some blocks that were rejected during the original run due to defect, were reborn as service blocks. Some were used as irragation pumps where the rpms were not enough to cause failure. Would love to hear from others more knowledgeable on this subject.

[Anthony]

FWIW,

I was told by a guy that by the late sixties, the 427 block tooling and molds were worn out, and there was core shifting and thin skirts with some of the castings. Ford knew they were D/C'ing production, and were in the process in making the 429 the new HiPo block. Rather than get all new tooling to continue production of 427's, which were deemed inferior to the new 429 engine, they made modifications to the old molds, incorporating ribs in the skirts to strengthen them up, as thin skirts was one of the problems of later 427 castings.

Not all replacement blocks had or needed the ribs. I believe the GTE cougars in '68 came with 427 SO's, with hydraulic lifters, and no ribs as with some of over the counter replacement 427 SO's. You can take a hydraulic block, tap and block the lifter oil galleries, and/or run shell lifters, and run a mech cam. Obviously, if you don't have the hydraulic lifter galleries, you can't run a hydraulic cam.

I also heard that when Ford was machining a 427 SO block, and cut too deep when machining the driver side engine mount pad, into the SO oil gallery, they then finished drilling the block out as a top oiler, and used it as a marine engine.

[SCOBRAC]

Service blocks were offered throughout the latter life of the 427, as they are with every engine. Go to a Ford catalog today. They offer 351 blocks, 302 and 4.6L blocks.. Were some released that shouldn't have been.. Sure, as with everything.. We have all heard about Monday morning and Friday afternoon products of all kinds.

427 service blocks always had the latest design revisions for their type. My 1966 (sept 1966) is fitted for hydraulic OR solid lifters, this didn't make it to production line 427's until 1968. My block doesn't have a engineering number cast into it, i.e. C6AE.. Does this make it worth less? Why would it. Late production service blocks had thicker cylinder walls and are stronger by the employment of squared off cylinder wall castings as opposed to the round ones from 63-65..

If you are looking for an "original" Cobra engine block it won't be found in service block.. But neither are any of those you have seen offered for sale either..

Regards,

[Chaplin]

Scobrac-
Forgive my ignorance, but if your block does not have a date code on it, how do you know that it is a '66? The reason I ask is that I am looking for a '66 or '67 428 block to rebuild, but was told that I could not use a service block b/c they did not have date codes.
Thanks,
Mike

[BLACKJACK]

HI, MIKE:

THE ENGINEERING NUMBER AND THE DATE CODES ARE TWO DIFFERENT THINGS.

THE DATE CODE ESTABLISHED (VIA A CASTING NUMBER) THE DAY MONTH AND YEAR THAT A BLOCK WAS "CAST".

MY 427 S/O IS MOST LIKELY A SERVICE BLOCK BECAUSE IT HAS THE CAST-IN VERTICAL RIBS ON THE PASSENGER SIDE - FORWARD ON THE BLOCK; ALSO, BECAUSE IT HAS A DATE CODE FOR APRIL 1968.

I TOO HAVE HEARD THAT THE ADVANTAGE OF THE LATER BLOCKS WAS THAT THEY INCORPORATED EVERY IMPROVEMENT DEVELOPED THROUGHOUT THE PRODUCTION RUN. ADDITIONALLY, THE VERTICAL RIBS WERE A LATE IMPROVEMENT - NOT A COMPENSATION FOR DEFECTIVE CASTING. CORE SHIFT IS SOMETHING THAT COULD TAKE PLACE AT ANY TIME, IN ANY YEAR, ON ANY BLOCK AND IS NO MORE LIKELY TO HAVE OCCURRED ON A 1968 SERVICE BLOCK THAN ON A 1966 PRODUCTION BLOCK. BECAUSE OF THE ALREADY SPARSE WALL THICKNESS ON THE 427, CORE SHIFT BECOMES INHERENTLY MORE CRITICAL THAN WITH OTHER BLOCKS.

I HAVE A REALLY HARD TIME BELIEVING (ALTHOUGH I HAVE HEARD IT SAID BEFORE) THAT FORD MOTOR COMPANY WOULD "JURY-RIG" ENGINE BLOCKS THAT WERE DETERMINED TO BE DEFECTIVE AND THEN PASS THEM OFF INTO THE MARKETPLACE.

Y'ALL HAVE A REALLY GREAT DAY,

BLACKJACK

[cobra427hp]

I purchased several 427 service blocks when Ford was closing these out in the 70's. The main problem I encountered was the horrible casting with too much silica which caused the blocks to fall apart around the motor mount bosses and along the side oiler system. I paid a ton to get these repaired and have stayed away from service blocks since. I'd rather pickup a used block put in 8 standard sleeves, and know I've got a tried and proven block. I am leery of the new aluminum block due to all the stories I have read about the machine problems even though the weight loss would be great.

[Chaplin]

Here I go being stupid again, but does a service block have a date code on it? For instance, if I used a service block from '66 or '67 would I be able point to a date code on the motor to prove to DMV that the motor really was a '66 or '67?

Thanks,
Mike

[thundercat]

I have a 428 service block in my car --- has ribs both sides-- NO engineering number-- but has date code cast under oil filter boss on side of block[ 1972] This block was still sealed in box when I purchased Stve McD

[BLACKJACK]

HI, MIKE - -

I BELIEVE THAT ALL 427'S HAD THE DATE/CASTING NUMBER LOCATED NEAR THE OIL FILTER BOSS. THE NUMBER WILL BE A SERIES OF NUMBERS A LETTER AND ANOTHER NUMBER.

THE FIRST NUMBER IS THE DAY OF THE MONTH, THE LETTER REPRESENTS THE MONTH AND THE LAST TWO NUMBERS ARE THE YEAR. THE LETTERS ARE "A" THRU "M" WITH THE EXCEPTION OF "I" - WHICH COULD BE CONFUSED WITH THE NUMBER "1'.

EXAMPLE: MINE IS (AS I RECALL) "4 D 68" WHICH MEANS THAT THE ENGINE BLOCK WAS CAST ON THE 4TH DAY OF APRIL 1968.

THIS NUMBER SHOULD WORK AS FAR AS ESTABLISHING THE YEAR OF YOUR ENGINE FOR THE BUREAUCRACY.

Y'ALL HAVE A REALLY GREAT DAY,

BLACKJACK

[Chaplin]

Blackjack-
Thank you sir!

You too have a great day!

Mike

[427SSSS]

http://www.fomoco.com/forumfe/result...ervice%20block

[DougD]

"I've seen several people selling 427 SO. Some are advertised as service blocks other have been listed as NOS. What exactly is a service block?"

A service block is one that was not originally installed in a vehicle on the production line. It is a repair, or service, block sold through a Ford dealer's parts department or similar. If unused, it would be NOS by definition. A NOS part is a FACTORY part that was produced back then, is not in production now, and is in unused condition, presumably good as new. It's possible to have a NOS part that is damaged, corroded, etc., but that should be indicated by the seller, as the assumption is it's good as new. Many people claim NOS on parts that are still available from the manufacturer. To be NOS, it must not be available from the manufacturer's replacement parts program.