You can always submit your measurement after placing the order. For now, just select Customize with Made to Measure, click Add to Shopping Bag and complete order. Later on go to Account section, visit My Orders page and submit your latest measurement.
If your bare chest size measurement is 40 inches, you should select size 40 only from the product page. The "Top Chest" attribute in the size chart refers to the garment's chest size. It is inclusive of the required 3 to 4 inches loosening, to ensure the right fit.
If your bare chest measurement falls between 2 sizes i.e 37 inches, you should select size 38.
https://www.utsavfashion.com/product/embroidered-art-silk-kurta-set-in-dark-green-mgv596982815Embroidered Art Silk Kurta Set in Dark Greenhttps://medias.utsavfashion.com/media/catalog/product/cache/1/small_image/295x/040ec09b1e35df139433887a97daa66f/e/m/embroidered-art-silk-kurta-set-in-dark-green-and-beige-v1-mgv596.jpg00USDOutOfStock/men/men/plus/men/wedding/men/festive/men/art silk/men/green/men/kurta pyjama/men/resham/men/traditionalEmbroidered Art Silk Kurta Set in Dark Green <ul><li> Readymade Art Silk Kurta in Dark Green</li><li> This Collar Neck and Full Sleeve attire is Prettified with Resham Work</li><li> Available with an Art Dupion Silk Churidar in Beige</li><li> Do note: Dupatta and Footwear shown in the image is for presentation purposes only. Half to one inch may vary in measurement. (Slight variation in actual color vs. image is possible)</li></ul>USDtype_new:Kurta Pyjamacolorfam:Greenfabric:Art SilkGreenArt SilkKurta Pyjama11%-20%MenMore than 15 DaysReadymadeWedding, FestiveMenswearResham, Traditional44