if i can't even get the name right everytime, and i never use them as i'm in the UK a link isn't gonna be easy from me lol
i can give you Weston www.westonuk.co.uk and if i had to guess... www.modelbaul.com ?

it's not a buget engine tho, esp as that price isn't with the pipe.
i'm not sure what my second choice 50 size engine would be tho if i wanted cheaper than the OS