360 magnum to 408

3 7/8 is 3.875....never seen a mp crank with that stroke...4 inch yes...3.79 inch yes..

as far as the pistons being out of the hole...it is in the math...

the 360 has a deck height of 9.600 approximately...

rods are 6.123

stock 360 pistons have a compression height of 1.66

the math.... 1/2 the stroke of 4 inch is 2 inches...plus the rod 6.123 plus the compression height 1.66....is 9,783

9.783 - 9.60= 1.83 ...the piston will be 1.83 inches out of the deck...it will be hammering the head...

you need pistons with a compression height around 1.45 for a 4 inch crank...

3.79 /2= 1.895 + 6.123 - 9.60 = 1.58 compression height pistons are needed for a 3.79...

stock 360s are 1.66....again...the pistons will stick out of the bore...