1973 scorpion super stinger 440

[joshua16]

i'm asking for my father but he decided to pull his sled out of the crate its been hiding in for 11 years.we cleaned it up and put new gas in and let it set for 14 hours then pulled it over a couple times and it fired up and ran fine then shut it off and took it out of the garag the next day fired up good then he took it around the field one time then it started to bog at low speed but is fine at high speeds then we started to tear it apart and the silencer cap had come off we put it back on and it still ran bad at low speeds dad thinks it mite be the crank seals any ideas.joshua

[JDT]

Any engine that sat that long could have dried out, cracked or leaking crank seals.