Thumper Power Risers (Polished) 

Thumper Power Risers (Polished) (Sold in pairs)

IMCO's affordable alternative to stock cast iron Chevy risers. Our all cast aluminum risers will increase Horsepower, RPM, and Torque by 5 to 7% over stock cast iron manifolds and risers at a fraction of the cost. We have designed Thumper Power for everyone whether you're a high performance or family recreation boater. Kits are available for Chevy big block, small block, and V-6 motors. Available in black powder coated, optional hard anodized for corrosion (prior to powder coat), and polished. (SOLD IN PAIRS)

Shift, EFI, or ECM brackets sold separately.
When using these risers, it's best to order 2 each 02-2242 oval hoses for wishbone connections.