250 Inline 6 is SLOW

[Matt Man]

So I set the timing at 14 degrees drove to the gas station and no change was made. Came back home, took the distributor cap off and checked the advance weights and they move freely and were greased properly. Verified timing and advance and still no change. I then set the timing at 10 degrees and drove it and still no change. I always thought the air filter was small and I did change the paper element about a year ago. Anyway, on my test drive I pulled over and took the air cleaner off and good lord it feels like I gained 30 horsepower. Laid a "one wheel peel" for about 30 feet from a stop sign! So it looks like a new air cleaner is in order. I guess I will see if a new air cleaner will help. Does anyone know what the max rpm is for a stock 250?

Edit: the power wire to the distributor does have 12 volts with the key on. The truck has been rewired before I got it so I figured that was ok but checked anyway.

[Steeveedee]

If that tiny filter was restricting airflow that much, you're going to have a leaner mixture when you get a bigger one, which would be an improvement as well. Good to see you found the culprit!

['68OrangeSunshine]

If you're happy with the stock carb/ intake/exhaust configuration, once you get the air cleaner sorted out, that's cool.
But there's a hellova lot more power to squeeze out of these L6s in the aftermarket.
I have an Offy intake, Edelbrock 1404 500 CFM carb, Clifford headers and HEI.
Also rebuilt the original 292 motor to .030 over, 1.85'' intake valves [1.6'' is stock], Crane 260H cam.
I'm in Tucson, AZ at 2700'. I run 12* advance.
Check out these sites:
www.inlinersinternational.org
www.cliffordperformance.com
www.12bolt.com

[jayoldschool]

Shouldn't be too hard to find a stock air cleaner housing for it. One more thing, now that the timing is increased to where it should be... have you also opened up the plug gap to match the HEI?