Engine identification..driving me mad

[Prophead]

I know this question has been asked many times, and I know there are numerous lists out there (I have read many of them) but I still cant identify excatly what my engine is or where it came from because it doesn't match up with any of the lists. The original builder of the car claims that it is an 3.5 RV8 from a TVR 350i (Wedge) but the code doesn't match. As for the heads, no idea. Anyway, here are the codes, perhaps one of you gurus out there might recognise them:-
Block 11A55152 CR 9.75:1
Heads (as best I can make out) ST3150 which is stamped in the front lower edge of the right hand head (no casting number), I cant see the front of the other head as the Alternator and bracket are in the way.

Any help appreciated. Identifying the origins of the engine will help me work out the kind of performance I should expect from it once I get tuning dialed in.

[harvey]

I think you'll find 11A is SD1 auto, and that CR was on the Vitesse engines.

[Prophead]

I think you'll find 11A is SD1 auto, and that CR was on the Vitesse engines.

The Vitesse engine number would be 31A......according to 'the lists' as an auto with 9.75:1 CR

this is why its confusing

[harvey]

Hmmmm....