Flat tappet to solid roller...

He did say he was waiting in new ones and these are just for engine break in.
Yes, I understood that. I wouldn't fire it again until the correct pushrods were in the engine. I wouldn't splice a drive shaft and I wouldn't splice a pushrod and run it in an engine, no matter how pretty they looked. One of those splices comes off and wedges itself between a roller and cam lobe and you have a real break in. I've tried to not hurt peoples feelings and had them blow up their engines. I'm tired of that. A bad idea is a bad idea.