I should have tried to measure a bore when the pan was off. The valves are GM units which is the reason a took a picture of them. It looks like the engine was mounted using the studs coming out the front of the block.

The blower that I put on the engine on the last couple pictures is mounted to an original GM dual quad intake and the ports don’t come close to matching up. The ports on the heads are much higher.

Thanks,

Jason

'

Heads may be later but O# Casting Alloy SB's bring the CERV cars to mind.
Cerv-1 w/ Alloy 283 was likely an Alcoa O# Casting as pics of one a guy had in his Corvair at this link...
https://www.hagerty.com/media/automo...-into-corvair/

Cerv-2 program parts may better fit subject if you can find info/details?
The 1990 Cerv-3 Corvette was reportedly a Lotus built Alloy 350 so may fit uncommon Flat Crank piece of the puzzle?

A few questions;
How long did GM use O# Castings?
Was there leftover/unfinished 60's O# Alloy blocks available late 80's to supply Lotus?
Did GM still have Block Castings to make new Blocks 70's/80's w/ changes/modifications?
What specific GM Alloy SB's were Chaparral or other Racers using 60's/70's/80's?
Do the CGT4 CONV1 Castings help indicate timeline also is the Block w/ same #'s at this link a brother or perhaps someone previously seeking info on this same Subject Block...
https://www.camaros.net/threads/gm-a...-block.124075/

Any truth to the Military Alloy SB's mentioned in above link and what parts were they using?
Whether info correct or not, did you see this 2012 Camaros.net posting...
https://www.camaros.net/threads/alum...engine.214727/

Keep digging Jason, super interesting stuff and looking forward to what you figure out!
:beers:
~ Pete

.

Thanks Pete,


I had come across the articles you attached in my searches but there is not much concrete info. The military theory is a possibility but I don't think it would have an O casting in that case.

Here is the one that Heartbeat City posted but that all the info I have on it:

https://twitter.com/hbcitycamaro/sta...52115568164864


Thanks,


Jason

Jason, I’m guessing the short block is IndyCar type to meet the stock-block rules.
Scale the stroke, should be approximately 2.2”. In the early 70s they were experimenting with the flat plane crank and the engines displaced about 207ci.
Below is a link to an old ad for one Smokey Yunick built.
https://grassrootsmotorsports.com/fo...e/37588/page1/

Rob,

That is interesting. I bet the stroke is pretty short since the block has reliefs for the rod bolts but the sleeves are not clearanced in these areas at all. I never thought it would be that short though. I will check the bore and stroke the next time I am near the engine.

Thanks,

Jason

Didn't Al Maynard have one of these?

I saved some Pictures years ago.
I think that its in a Museum.
Cant remember.

Thanks. That looks like the same one Heartbeat City had posted.

Jason

Hi...Yes, I saw an aluminum SB in a early 30"s Ford when I was there. I asked him about it, said he got out of the GM tech center in a load of scrap!!!!!

I'd never seen a 2-4 Z28 set up in Canada till that day. He had so many I couldn't count, 20-30, with air cleaners. A pile of Muncie transmissions, 25-30 brand new and at the time the largest Mac tool box I had ever seen in his garage, over 6' long and close 6' high. They are "everywhere" now....Early 90's

https://www.motortrend.com/how-to/19...l-block-chevy/


1963 All-Aluminum 377 Small-Block Chevy article