MY SCENARIO!!! WHAT WOULD YOU DO?

Im new to this forum but have read a few posts here, quite interesting.

Ive got a scenario i wish to get advice from

I have my own property in which i owe 100k on and i have another property that i have just finished subdividing with my father, in which it owes me 350k for my block (we done a 2 lot subdivision) and i could possibly sell it for 650k , so if i sell i could pay the house off and have 200k in bank,

if i keep it ill have a total 450k debt and probably have to pay interest of about 30k a yr (i only get 150 a week from rent on that property, its only a granny flat)

i do speccies and thats how i make my money, building spec homes, and that was the first subdivision, quite lucrative, i would recommend subdividing to anyone

any other time i would ust sell and take the profits, but its in a good area that got not much supply and heavy demand, BUT

im trying to work out if it will achieve a capital gain of at least 30k a yr , plus if i had the 200k in bank i could make money on that or use it to do another speccie

im very cautious with interest rates at the moment and i dont want to have to much on the go and leave myself exposed.

im trying to work out if this is a property to hold on to, could be good capital gains in the future

so…… here it is in short

PPOR WORTH 450K OWE 100K
INVESTMENT PROP WORTH 650K OWE 350K RENT 150WK

doing the numbers it would have to go up at least 40k a yr to make it worthwhile. could anyone see that happening

id love to hear your thoughts,

markus