Plus the extra cooling holes around the plugs 'as per 452 motorhome heads' too.

I did run this engine in the 90's at the famous 'Santa Pod raceway' UK.
But the valves were way too short for any 'meaningful' camshaft use, best was a 509 DC hydraulic.

Then I found out the valves had been 'remade' by a previous owner at standard 440 length which was 0.250 too short!
So now I have had some longer valves made so I can use 2.000'' valves springs and a 0.650 roller.

Folks have been wanting to know what flow they have?
Don't actually know this fact as all the paperwork was lost when Weslake Engineering 'shut-down'.

I guess around 300cfm's as they are 'rough cast' and will need some port work to get the best outta them?

The rumour was they were in 'hemi-territory' as a replacement when the Hemi got banned in Nascar?
The Wingcars and other issues of the early 70's put paid to much of mother Mopars development work...