All of those cams are very mild with very slow motion in inches of lift per degree of rotation.
The 235 & 261 connecting rod to stroke rod ratio is fairly long at 1.73:1, which makes piston motion near TDC relatively slow (and faster near BDC) in inches of lift per degree of rotation.
At 11.5 degrees from TDC the piston has moved about .051".
For any the following changes reliefs in the dome may be needed:
1. milled block
2. milled head
3. larger valve OD
4. higher rocker arm ratio (than 1.477:1)
5. cam advanced
6. more intake duration
7. more lobe height
