Hello y’all, Came to see if any one can help me trouble shoot.I swapped a 5.3ls into my 81 c10 starts up fine and rev completely in park or neutral.but when put in gear it moves fine but it will only rev too about 2500-3000 rpm .Any tips to troubleshoot im kind of a newbie to the ls platform.ANYTHING HELPS.

 

Have you verified correct fuel pressure at the fuel rail?

 

".Any tips to troubleshoot im kind of a newbie to the ls platform.ANYTHING HELPS."
Yep. Try the diagnostics/tune forum.