[Aussie Mike]

They experimented with a DOHC motor in the Corvette. It used heads designed by Lotus.

What they found though is that they could make a wedge style head that flowed just as well as the DOHC heads without the added complexity and weight. That SB2 head that Alffie mentions has a lot to do with it's design. Valve angles had been reduced allowing higher comps with a flat top pistons while keeping a better combustion chamber shape. The old SB chev had a 23 degree valve angle where SB2 is 13 degree and LS1 is 15 degree.

The result is a push rod engine that makes as much power as it's more complex DOHC rivals in a package that weighs significantly less and is significantly smaller.

The LS1 weighs nearly 100KG less than the Boss 290.

In width the LS1 is Scarlet Johansen compared to the Boss290 Magda Szubanski...

As for similarities between Cleveland and LS1... that doesn't surprise me. Bore spacings are common across quite a few motors out there and with the standard 4 hold down bolts per pot there aren't that many patterns and spacings to choose from.

Port design and valve sizing it doesn't surprise me that there are some common sizes. The experts have determined long ago that there is an ideal ratio between intake and exhaust valve sizes and cylinder bore sizes.

I'm just glad we don't have the Clevelands awful exhaust port design and over sized intake ports.

Cheers