Service Blocks

[dcdoug]

Sorry for the newbie question, but what exactly is a 427 service block and why do people seem to look down on them? Are they considered NOS or something different? How did the quality of these blocks compare to the originals?

[Ron61]

Basically a Service Block for any type engine is new ones that the companies made the year of the cars they came in for replacements in case the original engine blew up or had a defect in it. They won't have the codes that tell which car or truck they came in as they had no way of knowing which vehicle may need a new engine. They are as good as the originals, just don't have the stamping on the block, so any person familiar with a car and it's date codes would be able to tell if the engine was the original one or not.

Ron

[dcdoug]

So in the case of replica or continuation Cobra motors which aren't original to the car anyway, why do some look down on service blocks?

[Ron61]

The best answer that I can give you is that they want everything to be as period correct as they can get it. Take an aluminum Kirkham or CSX for example and if you want it to be as much like an original as you can get it, then the service blocks wouldn't have the coding on them that is needed.

Ron

[dcdoug]

Are the service blocks still considered NOS, especially in the case of the 427 when they stopped making them in the late 60s and then did an additional run in the early 70s?

[FWB]

Doug,
are you looking at one? to purchase. there are some slight differences, some cosmetic, some not.

[undy]

Originally Posted by dcdoug

Are the service blocks still considered NOS, especially in the case of the 427 when they stopped making them in the late 60s and then did an additional run in the early 70s?

NOS, (new old stock).. They'd be considered NOS if they were new and unused. I'd heard on some of the later 427 "service blocks" core shift was a greater problem than the earlier runs, nothing hard to substantiate that though.

BTW... Some of the 427 service blocks (irrigation/pump duty intended) were not "cross-bolted", simply the 2 bolt bottem end with press-in freeze plugs too.

Dave

[dcdoug]

I have a guy who is building me an engine using new/used NOS 427 side oiler block, NOS heads, NOS TRW pistons, NOS LeMans rods and NOS 427 Crank. Before assembly, I am researching everything to be sure I am getting what I am paying for, which seems to be the case. I will post the numbers and date codes when I get them and any feedback you have would be appreciated.

[FWB]

to each his own i always say but, why the trw pistons and lemans rods. the weight of that assembly is going to be high.
TRW's, heavy hard pistons. will wear the walls, and prone to skirt cracking.
Lemans rods, heavy, 40 year old metal. 700 plus grams each.

i can see heads and crank....fine , but you should at least look into other rods and piston combo's just for a reality check.

[computerworks]

Originally Posted by dcdoug

.... using new/used NOS 427 side oiler block, NOS heads, NOS TRW pistons, NOS LeMans rods and NOS 427 Crank.

I think you might be correct to challenge his definitions.....

new/used NOS 427 side oiler block

...come again?

Service blocks were made for several years after actual production units were made...as spare parts. Some say they were not as well cast as the early ones.

With respect to "NOS" blocks...40 years after they were made...
...I know in my business "new-old stock" stays in the warehouse because they were either customer returns or they had problems and just put it back and grabbed another one.

Also remember a part is only NOS until you use it....then it's just a regular old used part.

[dcdoug]

Sorry, I mistyped, meant new/unused.

[computerworks]

...................

[patrickt]

Originally Posted by dcdoug

I have a guy who is building me an engine using new/used NOS 427 side oiler block, NOS heads, NOS TRW pistons, NOS LeMans rods and NOS 427 Crank.

You don't see that too often (meaning the use of NOS innards). It will run on pump gas, right? What sort of cam are you putting in it? Where did he get all that internal NOS stuff? Did he already have it or did he find it for you?

[Anthony]

Originally Posted by dcdoug

I have a guy who is building me an engine using new/used NOS 427 side oiler block, NOS heads, NOS TRW pistons, NOS LeMans rods and NOS 427 Crank. Before assembly, I am researching everything to be sure I am getting what I am paying for, which seems to be the case. I will post the numbers and date codes when I get them and any feedback you have would be appreciated.

I'd have the block's cylinder walls sonic checked for thickness to make sure there is no core shift issue, as there are new blocks available much stronger, thicker, and heavier, than the original. I don;t think I'd use the lemans rods.

[patrickt]

DCDoug -- are you sure you don't want to shave a little weight off that build?
See: http://clubcobra.com/forums/showthre...514#post951514

[dcdoug]

Yes, it will run on 93 octane pump gas. The cam will be custom ground and will have decent street manners. He's a regular engine builder for the Shelby dealer I am buying my car from and has been building 427s and 428s since 1968. He specializes in only those engines. He had the NOS rods and pistons (bought them years ago and saved them - he still has a number of NOS 427 and 428 blocks as well) and I just thought it would be neat to have something as authentic as possible. I guess the weight is a tradeoff though.

[patrickt]

Originally Posted by dcdoug

... and I just thought it would be neat to have something as authentic as possible. I guess the weight is a tradeoff though.

That's fine... and we go through this type of discussion all the time. It's the little things that makes someone happy on their build. Unless you're an all out racer, a hundred pounds (or a hundred horsepower) really doesn't matter.

[dcdoug]

Seems like 500hp will get me down the street alright, even with a few extra pounds up front.....

[patrickt]

Originally Posted by dcdoug

Seems like 500hp will get me down the street alright, even with a few extra pounds up front.....

Indeed it will. But, just so you know, if your builder puts the engine on the dyno with straight pipes (meaning no sidepipes or mufflers) and it shows 500HP, then you'll be well down in to the 300s on a chassis dyno at the rear wheels.

[Anthony]

Originally Posted by dcdoug

--- He's a regular engine builder for the Shelby dealer I am buying my car from and has been building 427s and 428s since 1968. ----.

Which shelby dealer are you purchasing your car from ?