73 cheySuper
Member
- Joined
- Sep 16, 2025
- Posts
- 49
- Reaction score
- 154
- Location
- beaverton
- First Name
- jerry
- Truck Year
- 1973
- Truck Model
- cheyenne super C20
- Engine Size
- 454
Pulled these off the 89 V3500 and set them aside. Then, today, I pulled the original manifolds off my '73 C20 454 and the difference in size is very noticeable, not the outlet, but the runners themselves and the log. My question is, has anyone flow tested these to give numbers to what I suspect is at least 10% bigger, and maybe the same percent less restrictive. Googled this with 0 results. I was debating headers or the old 73 manifolds, and was leaning towards headers but it's a puller, not a bogger so the gains at higher rpms don't mean much, but headers do have an advantage throughout the rpm range. These may be the answer??? The number on the pass side is 10045730, drivers side is out of reach for the moment.
