I measured the approx space between the donuts on mine, 2.5" here ... carb base on intake should be near level ... how's your distrib clearance? HEI or points? I couldn't fit an HEI on mine, too tight to the firewall

those manifolds sound like the corvette ones, bigger ports likely makes the exterior length more ... I've got some loose manifolds I can dig out and measure

Bill

Moved over to the Passing Lane

"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir
"When we tug a single thing on an old truck, we find it falls off" ~ me
Some TF series details & TF heater pics