69 C10 l6 lack of power with 4bbl, offy intake, exh manifolds

['68OrangeSunshine]

Originally Posted by Steeveedee

Good to see that it's working better, now. I was mistaken about the carburetor- I thought that it was a lot bigger than it actually is. 390 CFM on a 292 should be a good match.

Easy to get confused looking at the Holley 4160 series. Huge range of CFMs. 390, 450, 600, 650. If you want more flow, you can go for the 4150s and Double Pumpers. I think I blew the 350 V8 engine [PO's crate] in my other rig, a '71 GMC Jimmy K/1500, by putting a 780 Holley double pumper on a cast iron intake and then experimenting with ''Aviation/Racing'' gas (100 Octane) on my local streets. I blew out valves on both sides. #3 AND #6 IIRC. They said ''it sucked the valves...'' The tips of the spark plugs in those cylinders were smashed. I just bought me a fresh Mr Goodwrench crate and rocked on. On pump gas.