I'm looking at a 1972 Cutlass S that has a 1970 455 with it. The engine is out of the car and needs to be gone through as it has not ran for some time. I don't even know if the heads on the engine are 1970 they could have been changed at some time, is there any way to tell without removing the valve covers?

I have been reading up on the heads and it seems that some have hardened seats and some don't. I talked to a local machine shop and they are farmiliar with the 455's but he told me to watch out for the heads. He said some have seats that can be machined, some have replaceable seats, but some seats can't be repaired so they are garbage.

So what year/letter heads are the bad ones?

Or did I get bad advice from this shop?

Thanks

 

Letter E and below are considered good heads, not counting W30 heads. 442 and Toronados had larger valves. ID by large cast letter on end of head, no need to remove valve cover. Same people claim C heads are best of all.

Just my opinion and flame suit on: hardened/not hardened, unleaded/leaded...no real difference to the average enthusiast. We don't put enough miles on our cars.
Steve

 

Thanks for the reply Steve, yeah he mentioned something about the unleaded/leaded fuel and the seats, but he had lost me by then!

You have a good point I plan to build a mostly stock car, these motors are large enough as is don't need to do much mroe than a mild cam and maybe 10:1 pistons if it doesn't already ahve them.

I'll check the letter on the end of the heads to see.

If it was the original 1970 heads what letter would you expect to see?

And is there any reason to be scared of pre 1973 heads, or are they just as repairable as all the other 455 heads?

Thanks again

 

They should be E heads. The only heads to stay away from are the "J" smog heads. You cannot tell by the Letter if they are small or large valve heads. You will have to remove and look at them to know.

 

You cannot tell by the letter on SOME heads like the E heads while D F H and Ka only came in large valve varieties.

 

As noted above, with the exception of the J smog heads, all BBO heads flow about the same in stock form and (with the exception of D heads) have about the same 80-ish cc combustion chambers. Olds never used separate press-in valve seats on the SBO or BBO. All heads from the 1971 model year up used induction hardened seats. This is a process where the parent material of the heads is locally hardened for a short distance into the material. Your shop is correct in one sense - any cutting of the valve seats pretty much removes this small hardened area and you're back to regular cast iron. On an infrequently driven collector car, this will not be a problem - instead of needing a valve job at 100,000 miles, you'll need one at 80,000 miles.

 

Thansk for all the info guys.

It sounds like really their isn't as big of an issue as the machine shop was saying. If I had to get a valve job done then the car would still be good for a long time as I plan on using it just for a weekend cruiser.

 

On the topic of heads, I always wondered about the differences in the heads in 1971. There is a G head for regular cutlass/deltas with a 2.00" intake valve, and a G head on the regular 442/Toronado with a 2.07" intake valve. What is the difference between a large valve G head and an H head, besides $4,000 in value? Inquiring minds want to know. Thanks.

 

GREAT QUESTION???? I would like the answer to that on. Joe???

 

Isn't it f heads that are going for 4000.00? Reason beind is for an accurate restoration.

 

Yes, you are correct for 70 heads, I was referring to 71 heads on the W30s. (H) I am trying to determine what an H head has over a large valve G head. It must have some performance advantage or why would they bother.

 

4th photo from

http://www.ebay.com/itm/70-OLDS-455-...0f2ff0&vxp=mtr

Your 1970 heads should show the large "E" as seen on the observer's left when facing the engine from the side- fwd end of the engine's LH head or aft end of the RH head.

Other letters are not 1970 issue except F in which case rejoice.

See also

http://www.ebay.com/itm/1970-OLDSMOB...702910&vxp=mtr

showing that E heads will have rotators on all the valves.

 

So G's were generic heads, Ga's were 72 442's and the H was from 71 442

 

Ga heads were used on all 1972 455s and the are 3 different sized intake valve versions; 1.99 2.00 and 2.07.

 

I looked on 442.com, doesn't say that. They didn't put that info in?

 

442.com contains much that is inaccurate. Caveat lector.

- Eric

 

Okay, good to know. Thanks

 

h heads were specific to 71 w-3os only and easily get on or around 6000
71 442s got g heads I believe

 

Would be nice to come across those.

 

sorry but nobody ~easily~ gives up 6000 for heads LOL

 

So, no answers for the differences between an H head and a large valve G head? Somebody must know. C'mon experts.

 

Google it,may have answers

 

I'm pretty sure the "1.99" valves are the same P/N as the "2.00" valves.

 

If I recall correctly the 1.99s use a unique valve seat angle that differs from the 2.00 version.

 

The last set of Ga heads I had were 30 degrees intakes. But again those were Ga's not G's.

 

Lots of good info guys, I plan to go check the car out in a few weeks its a bit of a drive so I'll keep you posted.

Now question #2 is around the actual engine block, if it is in-fact a 1970, is there any identifying numbers or letters on it to tell this?

Is there a way to tell what compression pistons it has by the block number or letter?

I realize it could have been rebuilt or changed but assuming its original...

 

1.990 vs 2.000" is ten thousandths of an inch
That's "the same size" in practice.
I don't think the factory CSM lists three different intake valves for any one year of big block.



I looked on 442.com, doesn't say that. They didn't put that info in?
==================
Maybe... "they" is me and a few others, who compiled a lot of info to share for free on the internet when it was not so common. Well, you copy and paste, then get distracted, and forget to alter the pasted info into accuracy, and it gets shared, and shared again, and next thing you know it's got even more errors and typo's and is practically useless but readily found on the net. I had years worth of effort into a large Excel sheet compiling the CSMs' valve, cam, timing, etc. info into one big package, and a hard drive crash lost it all. I did not have the heart to start over on it, so I rely on the paper manual library if/when I need to look stuff up. 'Course nowadays we got the Wildaboutcars.com storehouse, which hopefully is backed up in the clouds.

 

The VIN-derivative engine number is located as shown, under the alternator on A/C cars:



There is no external notation of what the compression is, other than the "drill mark" on Toro engines, but in '68-'70 4bbls should be high compression and 2bbls should be low compression.



I don't know about the Cloud, but a whole lot of it is backed up on my laptop and backup drive. *whistles innocently*

I have absolutely no faith that anything on the interwebs will still be there tomorrow.

- Eric

 

I will check the carb and also look for that engine number. Is there an easy way to tell engine year from the number, like does one of the digits represent year or something along those lines?

 

30M123456 - 1970 Olds manufactured in Lansing, Michigan

3 - Division (3=Olds)

# - Last digit of year manufactured

Letter - Manufacturing Plant Code

###### - Sequential number, should be the same as the one in the VIN

- Eric

 

Perfect! Thanks again!!

 

Would this be an easier way to identify compression? I get the 4 barrel carb suggestion but if the carb was changed... I guess it all depends if the tape is still there.

 

There will be no tape on the oil filler tube.

If the pistons are original, you can look into the spark plug holes with a bore scope and check the notches on the forward edge - U-shaped for low-compression, V-shaped for high compression, as illustrated in the Chassis Service Manual.

- Eric

 

So I picked up the car this weekend, engine turned out to be a 1971 F block, with G heads 2.00/1.625 valves. It did have the oem 4 barrel intake on it (no carb) but the pistons appear to be be the low compression style so it looks like I'll be doing a bore job after I have the block checked out.

Just to confirm are these the low compression pistons?

The last pic also shows what I would consider the roughest bore, 3 of them are similar the other 5 are clean. The 3 are still smooth just have some marking on them. I'll have the local shop measure them up along with the bearings once I get it fully tore down...

 

Yup, those are the famous 40cc "cereal bowls."

You'll want different pistons for sure.

- Eric

 

I figured they were the low comp ones...

What is the weight of a stock piston and pin?

I found KB's are 635g piston and 163g pin.

SpeedPro 684g piston and anyone know the pin weight?

 

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