[PurelyGTO68]

Back in the 80s we used to build Pontiac engines and race them at our local drag strip. Sometimes we would search around for factory items that looked like performance parts and threw them together and see how they ran. Some of our friends did the same thing but with whatever brand they preferred (Ford, Chevy etc).

Those guys were always hell bent on starting with a 4 bolt block of whatever manufacturer they were running. We didn't really care that much. For most every power level we encountered....a well prepped 2 bolt block seemed to be plenty strong for our needs. We only raced 400 ci engines though. We tried some 350 and 455 engines but we couldn't get them to run as well as a 400. Other guys were pretty good at those other displacements but we pretty much stuck to a 400 ci engine and had a lot of fun with the hobby.

Every once in a while we would come across a 4 bolt block and we would set it aside for some 'monster' build that never happened. Other guys would usually offer us some ridiculous amount for the blocks, usually twice what we paid so we let them go. We came across them on a regular basis so it wasn't that big of a deal to wait for the next one to come along.

We didn't pay that much attention to casting codes and almost ignored the 2 digit block codes entirely. We mostly looked for blocks with 3 freeze plugs per side and 5 motor mount pads so we could have more options (we didn't always put our engines in Pontiac vehicles....). At any rate, I know I have one 4 bolt 400 block stored away and I think my uncle has 1 or 2 as well. My guess is that no one has touched these blocks for 25 years so when I go back home to visit for the holidays, I am going to try and dig them out and see if I can identify them.

So, now we are getting to my question....
I searched all my reference books and material and I don't have anything definitive that shows what cars came with 4 bolt 400 ci engines. I did find this listing online that appears to be fairly comprehensive...
http://www.pontiacpower.net/numbers/engine-codes/

So, I copied the data and put it in a spreadsheet so I can sort and filter.
I found about 376 different 400 ci block codes (2 digit codes) that is spread out over 9 different castings. I didn't see casting number 488986 (1975?) on this list so it could possibly be 10 or more different casting codes.

Of those 376 block codes....only 22 show to have 4 bolt main engines.
According to the data from the source listed above....all 4 bolt 400 ci blocks are ram air engines from 68 thru 70. However, I did read a recent post that a fair number of 1970 WT code engines were built as 4 bolt blocks as well. I presume those engines would have cast number 9799914 (??). If you group the 68-70 RA engines with these 'secret' WT 4 bolt engines...then we end up with 3 possible casting numbers.
9792506, 9799914, 9799915 (either 'as cast' or 'as stamped')

Does this sound correct? If so, then I suppose it's possible the 4 bolt blocks we have in storage are RAII, III or IV blocks? I don't remember for certain but I think these blocks have "400" cast in the side somewhere. I think this means they are likely 1970 RA III or IV or later SR blocks.

I say 'or later' because I suppose it's also possible (or maybe even likely) that some or all of these blocks could be service replacement engines. I am just beginning my research on these items. From what I have gathered so far...4 bolt SR engines could have date castings as late as 1973 (or even later?) but would likely have been ground and stamped with one of the 3 codes listed above. Is that correct?

Does anyone know of any 4 bolt casting numbers for 400 ci engines other than the 3 that I listed above?

Did Pontiac make 2 bolt and 4 bolt SR assemblies for 68-70 applications or were they all 4 bolt? Seems like it would be less complicated to make them all 4 bolt units so they could cover every possible application but that could then mean there were more SR 4 bolt blocks produced than original RA engines. Am I on the right track or am I missing something obvious.