Idles hot...

[YellowThumper]

Good to hear on the timing advance.
Yes pull that fan out from being shrouded fully.
If purchasing the factory shroud I would first continue with the solid fan you have. Note that fan cannot be too close in outer diameter to shroud. Your engine moves on its rubber mounts along with some from the trans mount.
My opinion is to avoid the flex fan as they are notorious for detonating from fatigue. Would suspect you may need a longer spacer to properly position fan fore and aft.
I have the 26" I had removed from mine if you want some dimensional and visual pics. Purchased 25+ years ago for my 74 so cannot confirm it is Ebody correct.

[Chryco Psycho]

I would spend the $$ on a 18" clutch fan & lose the flex fan personally

[RUNCHARGER]

Those Chinese aftermarket rads don't generally have provisions to mount a stock fan shroud. You'll likely have to fab something up. I know all the TV shows love to throw all the stock stuff in the trash and shotgun chinese parts on but there's reasons us old guys like the factory parts. I recommend a clutch fan as well. Hayden can supply a new clutch and fan if you go this route and don't want to spend mega $$$ on factory parts.

[chargerdon]

I would spend the $$ on a 18" clutch fan & lose the flex fan personally

Ok...couple of questions:

1) Thermal or non thermal clutch?   Im looking at hayden 1706 non-thermal or 2706 thermal...  only $3 difference in price so which one?
2) looking at 18" Derale clutch fan 17118
3) and the 2998236 reproduction fan shroud

any recommendations ?  Thermal or non-thermal.   Standard or heavy duty ?   

Am i going to need any spacers...and anyone know what size spacer.... 

Just want to do this once, and i have no experience with this stuff... 

[Chryco Psycho]

Thermal clutch 
Flex A Lite also has a 18 " 6 blade fan available , you may want to use the shorter Jag Clutch so the fan does not sit too deep in the shroud , no spacers should be nessisary .

[chargerdon]

do you know the number for the Hayden "jag" clutch ?

[Bullitt-]

do you know the number for the Hayden "jag" clutch ?

Discussed here  https://forum.e-bodies.org/parts-wanted/25/clutch-fan/16521/msg218558#msg218558