318 Four Barrel Intake

Do the math. The valves are in line and the bore space is.....
I have not ever had a 273, so test fit before fireing is allways the order of the day.

2.02 + 1.60 = 3.62
1.88 + 1.6 = 3.48

273 cid bore, stock, 3.63

3.63 - 3.62 = no way.
3.48 - 3.63 = 0.15 or yikes, whoa and other.

The issue with the smaller vale (1.88) is shrouding. Also the valve can wiggle a tad. A valve hitting the cylinder wall is more than bad.

Both do not included space between the valves. No matter how small.
I think BJR can answer this and other head work best.