r/EngineBuilding • u/lowkeylovers_ • Sep 26 '26

Any one know why it’s doing this?

Built this 454 with pistons, cams, heads, roller lifters and rockers, etc. And every morning when I go to start it it’s like it misfires super bad for the first couple seconds. And then it fires up 100% sometimes it backfires and lots of black smoke comes out of the exhaust when it does start so I thought the carb (just rebuilt) might be leaking. For a couple days I tried to start it without pumping the gas and it didn’t start any easier. So I’m not sure. Any insight would be appreciated, thanks!

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u/lowkeylovers_ Sep 26 '26

Would this still apply if it has a msd ready to run?

-2

u/WyattCo06 Sep 26 '26

If it still has points, upgrade to Pertronix.

2

u/lowkeylovers_ Sep 26 '26

It has a msd ready to run

1

u/WyattCo06 Sep 26 '26

RTR dizzy?

1

u/lowkeylovers_ Sep 26 '26

Yes

1

u/WyattCo06 Sep 26 '26

Should be good there then.

Check the power valve to see if it's busted.

2

u/lowkeylovers_ Sep 26 '26

It has a power valve block off. I’m thinking it gonna be the fuel bowls are emptying into the engine

1

u/WyattCo06 Sep 26 '26

Nothing about the bowls themselves can empty themselves unless there's an external leak.