Looks like with the early head I no longer have the return to the exhaust port for discharge. I would need to link the the center vertical passage in the the head to the discharge port as the thermostat head does. That vertical passage has a plug in the top, so if I remove the plug and pipe it to the open hole I may have my problem solved. I'll do a little more investigation into this. Thanks for the replies! ****
Now comes the "but", since it's all going into the CD15 chassis I needed the head with those ears sticking off it for the hood. I didn't get the hood with the CD20 and the ears on both sides of intake manifold were busted off where the recoil bolts up. So now I've got something that runs great, everything works, not a lot of $$ in it, lots of time and a sense of accomplishment.
