The Genesis is the way to go. Blocks runs cooler, is heaver webbed, can stroke it out to a monster 488cu in. I went with the Scat stroker to 452 cu in, diamond racing pistons ect. To go above this it becomes a torque monster and in such a light car as the Era it becomes useless. I can run pump fuel, 10.8:1 comp, with about 600hp on the street. Could never do it with the older blocks and iron heads except on racing fuel and that gets old real quick. Great souce for your Genesis build up is Precision
Oil Pumps,Madera, CA. Great prices on SCAT cranks, diamond pistons,
oil restrictor kits..great to deal with. Good luck on your build up..was down at Era three weeks ago and saw several Danbury engines on the floor waiting for installation.
Mark