[ALLTHINGSPONTIAC]

I was wondering if I could get some input from the Pontiac Engine gurus out there. I have a Pontiac 400 RamAir service block (What I was told) . The block has been magnifluxed and is in excellent unmolested condition. I was hoping I could get some help with Idenetification. Pictures are attached.
Thanks!

[Formulas]

Born Feb 22 1972

Its missing the third ( upper ) motor mount bolt hole lug for some reason on drivers side could be a SR for a year prior that doesnt need that full lug like a 1969 RA IV

Going to need a pic of the part number on the back of the block

pics of full lug and a part number

[steve25]

Pontiac service blocks came fitted with pistons , there was no other way to get a new block.

The RAIII 4 bolt blocks where the same as the RA4 blocks, but the RA4 blocks would have been fitted with TRW Forged pistons where as the RAIII motors would have had cast.

I hope you did not pay extra for a supposed RA4 block when like I said, a 4 bolt is a 4 bolt.

Did you get the pistons with the purchase of that block like you should have?

[JSuchma]

For some unknown reason, Pontiac would cut or grind off the upper motor mount boss on the ram air service blocks. I had a NOS one that this had been done to also. If I'm not mistaken, this has been covered here on this site before.

[steve25]

I believe the deal was that Since these post 1969 cast replacement blocks ( yours being 1972) where cast with 5 motor mount pads on each side ( to work in the 2nd gen F body cars ) that upper one had to be ground or machined off to work in the pre 1970 cars.

This also shows that the RA blocks and the post 1970 455 HO blocks where really nothing special other then being fitted with the nodular iron 4 bolt caps , and of course however they then needed to be machined.

[Rocky Rotella]

It's definitely an Service Replacement block and it appears that it will make a great foundation for a future build.

While NOS SR blocks were fitted assemblies and included pistons, this block appears to have been previously used, so who knows where the original pistons could be.

It was certainly created from a typical 481988 400 casting produced on February 22, 1972. The ledge behind the number 8 cylinder will likely have that ground away and the intended block number stamped in place. You're likely to find a "9799914" or "9799915" on it. Can you share a picture of that?

[steve25]

Rock I don’t know that the block was ever used since there’s no lines or marks that a Distributor was ever down in that hole.

[Ram Air IV Jack]

Originally Posted by Rocky Rotella

It's definitely an Service Replacement block and it appears that it will make a great foundation for a future build.

While NOS SR blocks were fitted assemblies and included pistons, this block appears to have been previously used, so who knows where the original pistons could be.

It was certainly created from a typical 481988 400 casting produced on February 22, 1972. The ledge behind the number 8 cylinder will likely have that ground away and the intended block number stamped in place. You're likely to find a "9799914" or "9799915" on it. Can you share a picture of that?

This block is worth a lot of money! There was always speculation that the RAIV blocks had a higher nickel content when poured for strength, but I've never seen solid documentation on that belief! I had one of these in the early 80's and it was purchased with pistons and pins. I sold it to the guy that bought my GTO the motor was going to go into. The price I asked for the motor with all the parts to make it complete was great for the time BUT horribly less than what I could sell it for today!!

[Rocky Rotella]

Steve, you might be right. I guess we'll have to see what the OP comes back with.

I was basing my comments mostly on the attached photo, which appears to show (a slight amount of) the typical corrosion around the coolant passage and the gasket shadows where the timing cover would reside.

[ALLTHINGSPONTIAC]

Originally Posted by Rocky Rotella

It's definitely an Service Replacement block and it appears that it will make a great foundation for a future build.

While NOS SR blocks were fitted assemblies and included pistons, this block appears to have been previously used, so who knows where the original pistons could be.

It was certainly created from a typical 481988 400 casting produced on February 22, 1972. The ledge behind the number 8 cylinder will likely have that ground away and the intended block number stamped in place. You're likely to find a "9799914" or "9799915" on it. Can you share a picture of that?

I will take a picture of that and post it

[ALLTHINGSPONTIAC]

Originally Posted by Rocky Rotella

It's definitely an Service Replacement block and it appears that it will make a great foundation for a future build.

While NOS SR blocks were fitted assemblies and included pistons, this block appears to have been previously used, so who knows where the original pistons could be.

It was certainly created from a typical 481988 400 casting produced on February 22, 1972. The ledge behind the number 8 cylinder will likely have that ground away and the intended block number stamped in place. You're likely to find a "9799914" or "9799915" on it. Can you share a picture of that?

Picture attached

[steve25]

That 3 digit 979 code was used from 68 thru 70.

[Rocky Rotella]

The 9792506 indicates that this particular SR block was intended for a late-1967, 1968, or early-1969 Ram Air application. That then corresponds with the engine mount boss being removed.

While the block itself offers no real performance advantage over any other 400 block of the era, it’s pretty valuable to the GTO and Firebird restoration crowd. And the 4-bolt caps are desirable if you plan to crank up the horsepower.

Can you confirm if it’s NOS or used?

[70geeteeohh]

Please guys go ahead and add your thoughts and input here but heres my thoughts on the Pontiac world of SR blocks.

Pontiac really hurt themselves with grinding/handstamping and doing a poor job at it. Anybody can order custom stamp sets off the internet relatively cheap.

Now I know people are going to say 4 bolt mains proves its a raiv block etc. But doesn't THEPARTSPLACE sell reproduction 4 bolt main cap sets that match the originals?

Seems to me a person can buy a run of the mill block and with some time and machine work turn it into a "rare" SR block cheaply and easily.

I personally have a few Pontiac block stampings saved in my Gallery file for comparison to one's that come for sale.

How does one prove an SR block to be legit?

[Ram Air IV Jack]

Originally Posted by 70geeteeohh

Please guys go ahead and add your thoughts and input here but heres my thoughts on the Pontiac world of SR blocks.

Pontiac really hurt themselves with grinding/handstamping and doing a poor job at it. Anybody can order custom stamp sets off the internet relatively cheap.

Now I know people are going to say 4 bolt mains proves its a raiv block etc. But doesn't THEPARTSPLACE sell reproduction 4 bolt main cap sets that match the originals?

Seems to me a person can buy a run of the mill block and with some time and machine work turn it into a "rare" SR block cheaply and easily.

I personally have a few Pontiac block stampings saved in my Gallery file for comparison to one's that come for sale.

How does one prove an SR block to be legit?

This is why you really have to scrutinize any of these block stampings. The RAIV WW block is the most counterfeited Pontiac block since most originals lost their lives in street/strip races decades ago. After 50 years, very few of these cars have the original motor or any part of the drive train because they were driven so hard years ago. Still, the "numbers matching" statement is used a lot today but better than an even bet, most of these claims are all BS!!

[steve25]

Here’s a tip off to the repro iron main cap deal.
Your not just dropping a set of them on a block and using the stock dowel pins in the block. Because things will not line up.
So to use the repro caps they are installed with oversized dowel pins and then of course the blocks main bores get honed or bored .

Also 4 bolt mains does not prove in anyway that a 400 block is a of RA lineage .

The 360 hp motors that where ordered with a 4 speed over the baseline manual 3 speed got 4 bolt mains also.
If you then go and look at the big 3.250” main motors like the 421, they all had 4 bolt mains as far as I know, and none of these ever had a RA prefix to there name, just HO.

All the 428 motors other then the 1969 motors that where born with the # 46 castings heads where all 4 bolt mains also, and all of these motors never had a RA prefix, just HO for the top of the line 428s with the 376 or 390 hp rating.

[PAUL K]

Originally Posted by Ram Air IV Jack

This is why you really have to scrutinize any of these block stampings. The RAIV WW block is the most counterfeited Pontiac block since most originals lost their lives in street/strip races decades ago. After 50 years, very few of these cars have the original motor or any part of the drive train because they were driven so hard years ago. Still, the "numbers matching" statement is used a lot today but better than an even bet, most of these claims are all BS!!

A lot of those original WW blocks ended up in Switzerland after they were blown up.... Some folks have figured out how to resurrect these rare cars after they have been scraped and crushed. All it takes is the Vin number and a willing participant at the DMV.

But it's still interesting to follow along.

[Burgess]

This block is the previous in sequence to a block which was for sale and sold on this forum a few months ago. 88043 and 88044. Same casting date too.

[70geeteeohh]

Originally Posted by Burgess

This block is the previous in sequence to a block which was for sale and sold on this forum a few months ago. 88043 and 88044. Same casting date too.

So if your information is correct about the sequence # isnt that a Red flag? Unless this block came from the same shop/collection?

[Dragncar]

Originally Posted by PAUL K

A lot of those original WW blocks ended up in Switzerland after they were blown up.... Some folks have figured out how to resurrect these rare cars after they have been scraped and crushed. All it takes is the Vin number and a willing participant at the DMV.

But it's still interesting to follow along.

Switzerland ?