About to refit cab, but...

[1G1YY]

I have my 62 chassis fitted with a 350 (TPI and HEI) and T700R all installed with pinion angle, shortened t shaft and rear mount all done.
All of the steering, fuel lines, exhaust etc is fitted up.
The old motor had a HEI dizzy fitted with no clearance issues between it and the firewall. I am ready to refit cab soon but I am unsure as to whether I need to modify the trans tunnel and low hump cover so that the trans will fit.
I don't have "rear" or "front" eng mount holes on the frame.
I set all up using the existing frame holes for the front eng mounts not knowing if they were in the rearward or forward location.
The only indicator I have is that the old dist fitted ok.
Can someone please let me know if I can go ahead and refit the cab without modifying the firewall?
Alternatively could I have measurements of the eng mount bolt(s) thru frame to a location towards front of chassis with a T700R fitted?
TIA