Just a bit of calculations.
The deck height of a 250 is 9.469". This is stock and doesn't take into account any milling.
A US250 rod is 5.880" long
A 2.5L Taurus rod is 5.990" long.
A 200/250 piston has a compression height (CH) of 1.50"
If you rebuild a 250 with stock rod and piston, the piston will be recessed 0.134" down the cylinder.
(3.91"stroke/2) + 5.880" + 1.50" + 0.134" = 9.469"
If you rebuild a 250 with a 2.5L rod and 250 piston, the piston will be recessed 0.024" down the cylinder.
(3.91"stroke/2) + 5.990" + 1.50" + 0.024" = 9.469"
This will help with your quench, and increase compression. The rod ratio also goes from 1.504 to 1.532.
If you go with a flat top 2.3L HSC piston (1.50"CH), the recess will be the same 0.024", but the compression will be significantly more.
Since you already have the 2.5L Taurus rods, this is the best way to go.
Another way to improve quench and increase the rod ratio in a 250 is 1965-68 300cid rods, and +1.0mm flat top pistons from a 2002-04 Jeep 4.7L OHC V8. The early 300 rods have a 0.9122" pin diameter, the Jeep piston has a 0.946" pin diameter so the small end of the 300 rod would have to be enlarged 0.0338".
And now the math:
65-68 300 rod is 6.210" long
2002-04 4.7L +1.0mm flat top piston is 3.701" in diameter with a CH of 1.24"
This rebuild will give you a recess of 0.064", less than half the stock depth.
(3.91"stroke/2) + 6.210" + 1.24" + 0.064" = 9.469"
This setup will increase the rod ratio from stock 1.504 to 1.588
The 65-68 300 rod does have a larger big end (2.2758" vs 2.239") so the 300 rod bearing would have to be used.
Hope you find this interesting.
Excel spreadsheet can be such a time-waster.
The deck height of a 250 is 9.469". This is stock and doesn't take into account any milling.
A US250 rod is 5.880" long
A 2.5L Taurus rod is 5.990" long.
A 200/250 piston has a compression height (CH) of 1.50"
If you rebuild a 250 with stock rod and piston, the piston will be recessed 0.134" down the cylinder.
(3.91"stroke/2) + 5.880" + 1.50" + 0.134" = 9.469"
If you rebuild a 250 with a 2.5L rod and 250 piston, the piston will be recessed 0.024" down the cylinder.
(3.91"stroke/2) + 5.990" + 1.50" + 0.024" = 9.469"
This will help with your quench, and increase compression. The rod ratio also goes from 1.504 to 1.532.
If you go with a flat top 2.3L HSC piston (1.50"CH), the recess will be the same 0.024", but the compression will be significantly more.
Since you already have the 2.5L Taurus rods, this is the best way to go.
Another way to improve quench and increase the rod ratio in a 250 is 1965-68 300cid rods, and +1.0mm flat top pistons from a 2002-04 Jeep 4.7L OHC V8. The early 300 rods have a 0.9122" pin diameter, the Jeep piston has a 0.946" pin diameter so the small end of the 300 rod would have to be enlarged 0.0338".
And now the math:
65-68 300 rod is 6.210" long
2002-04 4.7L +1.0mm flat top piston is 3.701" in diameter with a CH of 1.24"
This rebuild will give you a recess of 0.064", less than half the stock depth.
(3.91"stroke/2) + 6.210" + 1.24" + 0.064" = 9.469"
This setup will increase the rod ratio from stock 1.504 to 1.588
The 65-68 300 rod does have a larger big end (2.2758" vs 2.239") so the 300 rod bearing would have to be used.
Hope you find this interesting.
Excel spreadsheet can be such a time-waster.