engine wont run hot

[dgsadorset]

hi new guy here. i have a 1986 x19 1.5 runs ok cold when hot it starts to misfire and stops within 3 to 400 yds when trying to restart its as though it is trying to sieze up leave it to cool then starts ok. i have renewed plugs,(
ngk bpr6es) points, condenser, coil, fitted electric fuel pump, carb fan switch. any ideas i did read in a previous thread about block distortion what is that all about?