Nickey/Motion 427 Transplants

[Dan 68 Chevy II]

Have Popular Hot Rodding issue April 67 showing 67 Nickey Camaro 427.Shows picture of engine compartment and notice it was a original small block car by heater core,never change to big block heater core after 427 transplant.
Have Oct.68 speed and Supercar,Article on 68 Baldwin Motion Phase III Camaro and noticed the same on page 40 where it shows picture of engine compartment.
Was it more common for these 2 Supercar Companies to order small block cars for the 427 transplants.It kinda makes sense since they were putting 427 in anyway why pay the extra cost for
the big block car from the Chevy when the original big block is coming out.Front springs can be easily changed and SS rear suspension is the same on small block and big block cars.