It probably comes down to efficiency more than anything. I have a ball bearing GT2860R for mine, it's encouraging to see your results with a similar turbo. I'm thinking once my Pinto head is ported with big valves, a GT2871R will be the go

kcuf
nice work, saw a bunch of pages back that you ran a S4 RX7 turbo on a previous motor, a few questions on that, how well did it spool up? and at what RPM roughly if you recall? 
Did you run an external gate on it, or did you persist with the 10c piece sized internal gate?

main interest is that i have one on the shelf, and i also have a pinto mk3 cortina, just thought it would be a bit on the large side,

It made good power due to the size of the large rear housing, very little back pressure so the internal gate was fine upto 18psi.
It was a little laggy compared to wat i have now. if the engine had no load on it it wouldnt make boost. Under load it was quite good especially rolling the throttle on in second gear onwards. Just dont expect too much out of it until first gear is almost over.id keep the compression higher and run e85 fuel the results would be susprising just by using a turbo you have laying around.if chasing over 200kw probably not the ideal turbo to use.

Smaller rear housing of standard vl turbo would work alot better. Plus its a t3 footprint so easier to upgrade if wish to down the track where the s4 13b turbo has a unique bolt pattern on the turbine flange. Choice out of the two for street setup id pick the vl if you already have it.
Good luck with it, boost really brings a new lease of life to these older manufactured engines.enjoy.

kcuf
Yeah the s4 flange is terrible,
I converted my Slant six to EFI and used a S5 rx7 turbo on it with good results, made the car much more fun to drive, also a non standard flange though.

I'll see if i can still grab the VL t3, was given to me ages ago but never got to collecting it.
Thanks

Yes the s4 or s5 turbo works well on just about anything for a bit of extra power on .We put one on a stock 245 hemi years ago blow thru carb it made 165kw @ wheels on 12psi. But truckloads off torque. Thing was heaps off fun.

Any updates regarding new head/ port work?

GPW
Any updates regarding new head/ port work?

Not much progress of late . We have been running one of our cars lately which is also ford powered and turbod. Been having alot of fun with that and also had photo shoot on the mk1 for a magazine so got all that down first before more upgrades get bolted on.
Cheers