170 & 225 head swap?

So I finally got this done this weekend. Kinda set the valves but Im not too confident they are good, well unless it should sound like a tractor...if so she's perfect! She fired rite up so that was positive. Thanks for the help from those who commented.
PO had 2.5 liters of oil in it, although the dipstick says full it obviously has the wrong dipstick so Ive fixed that and added the 5 liters & marked the dipstick properly, that could make her sound like a tractor too as I havent started it back up since.

As I have never had a slant or drove this car I noticed when she warmed up that if you crack on the gas the revs drop almost instantly, like she dont hold any RPM at all, falls flat on its face when the accelerator is released. Is that normal?