I concur with ApacheFiend, once you have located the best TDC, you can mark the flex plate through the timing hole or make a mark on the balancer and improvise a pointer similar to the newer engines. It's only a place to start as you still can set the timing to where it runs best.
Fred


1956 3100 Pickup/Red/350/3sp OD/PS/Disc Brakes
1957 Bel Air Sport Coupe/Red/355/TH350/PS/Disc Brakes
2017 Silverado LT Single Cab SB/Black/5.3/6 Speed Trans
1947 Willys CJ2A w/F-Head engine