Godzilla 7.3L Swapped Cobra

[cycleguy55]

Originally Posted by eschaider

I think current Pro-Mod Rules use 4.500" as the bore spacing line of demarcation between small block engines and big block engines.

Here's what I see in 2021 Pro Mod rules relating to bore centre:

SECTION 6
E3 SPARK PLUGS NHRA PRO MOD
DRAG RACING SERIES PRESENTED
BY J&A SERVICE

ENGINE

internal-combustion, reciprocating, single-camshaft, 90-degree

V-8 automotive-type engine mandatory. Crankshaft centeriine must
intersect cylinder bore centerlines and be symmetrical. Nitrous-
assisted entries are limited to a maximum bore center of 5.300.
Maximum bore center on turbocharged billet hemi cylinder-head
entries is 4.840 inches, 5.000 inches on all other turbocharged
entries. Maximum bore center on supercharged billet hemi cylinder-
head entries is 4.900 inches, 5.000 inches on all other super charged
entries.

I see no distinction in bore centres between small block and big block, only between supercharged, turbocharged, and nitrous-assisted, as well as between "turbocharged billet hemi cylinder-head" and other turbocharged engines.