I am still at the early stages of getting the project off the ground. Arranged funds, and have found a chassis. All I need now is a suitable donor.
I've read loads about 1300 vs 1300 GT's, HC heads, LC heads, MkI vs MkII's. What I am trying to determine is what's the ideal donor car? I am guessing it will be a Mk II 1300GT escort.
any other suggestions?
FYI I aim to race next summer so it must comply with regs.

I would suspect that you won't be exactly spoilt for choice as finding an Escort donor gets more difficult by the day!!!
And since you will probably be rebuilding the engine etc anyway, you can set the spec yourself, within regulations.
There is a Locost Racing egroup which may well answer your questions but I would suggest you get the cheapest one available regardless of spec and budget to rebuild everything to blueprint standard.
I'm not sure how much differs but I used the diff and gearbox from the 1300 van when I used to rally to get better acceleration at the cost of lower top speed. We also used to use 1100 pistons and heads to raise compression etc. by 'eck i'm going back some years now.. when I was a lad... pass me my zimmer etc etc

I presume from that, the van's gearbox is ratio'd for carrying loads.

many thanks for the comments

the diff certainly is