Engine Block to Bellhousing Spacer Plate Question

I believe since that plate postions your starter, all three, flywheel, starter, and plate have to match.

The spacer plates are different between a 157 and 164. Starter bolts are in different position. I found one real quick by looking through the VMF Classifieds and sending a few e-mails. Most junkyards will have them also. 164 was used behind alot of 351C trucks.
I would not run without it as it might effect input shaft depth and shields you clutch against and main seepage.

Well, on my six banger with C4 the flexplate cracked twice. I put the spacer plate back in and so far no problems.

I agree that you must use the spacer plate and it should be the correct one for the larger 164 tooth flywheel. However, back in the early 70s, I converted a SBF for a boat and used a marine bellhousing that was made for the larger flywheel. I only had the small plate, but used it anyway by cutting off the starter area (where the two starter holes are located) of the plate so it could be moved out a little to match the holes in the larger bellhousing. So it became a two piece plate. It worked OK for this installation for over 10 yrs. At the time, I didn't know if it would be OK or not... but since there was no internet to surf, I just did it that way.