[Ramairnacho]

I'm trying to figure out stock specs of a 1970 trans am with automatic transmission radiator code Fs. And the difference between the fs and fx. I was told the tanks the same so I was thinking of having mine recorded to fs specs to run cooler than fx tank I guess. Or is there a better upgrade with stock external parts? I have a new repop but I want to run a Harrison radiator now and I have 1. Anyone know or can I get advice thanks

[Ramairnacho]

Here is a tag pic of one I got. Is it possible to.turn it into an FS?

[Baron Von Zeppelin]

Take the radiator cap off and shine a bright light inside , look to see if it has 3 rows of tubes or 4 rows.
Usually that is the difference in the codes per application.

[Formulabruce]

Run 17 cc dish piston with your heads, gets you right at 9:1 CR. Then drill the block in the middle, and head for coolant at middle ( part of the 421 mod) and run the upper radiator core baffle for 70 and you'll be fine with a 3 core with AC. And a 170 t stat. Have done this and works well for a driver

[Ramairnacho]

Thanks Bruce, I'll look if it's a 4 row radiator and if it's not I'll just run a repop. I worry about doing any mods since it's a number matching block. If it was a non or hot rod I wouldn't care but when my engine was rebuilt I only had them.bore it out 20 thousands. I honestly just wanted it honed. I'd be stressed about drilling out the block water port thou.

[Ramairnacho]

Originally Posted by Baron Von Zeppelin

Take the radiator cap off and shine a bright light inside , look to see if it has 3 rows of tubes or 4 rows.
Usually that is the difference in the codes per application.

I took the original cap off my 400 l65 esprit and it has a 4 row Harrison radiator. What is the difference 🤔 between FS and FX?

[Baron Von Zeppelin]

I don't know the codes/applications for these by heart and haven't had access to my files for quite a while now.
But if your FX is a 4 Core Automatic
Then FS could be 3 core Auto , or 3 core Manual , or 4 core Manual.

In the present, your FX is a winner and your worries are over.

[Held for Ransom]

The '70 Firebird V-8 radiators are
FL (maybe 2 core), FO (maybe 3 core), FM (also used for manual trans with plugs in cooler)(maybe 3 core), FX (maybe 4 core) and FS (maybe 4 core).

[Baron Von Zeppelin]

I've posted some 70 Van Nuys Bsheets before , going through my attachment history on here looking for them.
So far found a 70 YS Auto , Non AC
Radiator code = FO in box #46

That would be 3 core Auto

[Baron Von Zeppelin]

70 YZ Auto AC
= FX in box 46

4 core Auto

[Baron Von Zeppelin]

70 WS 4spd AC
= FP in box 46

4 core Manual

[Baron Von Zeppelin]

Went back through all 1500+ attachments I have on here and those are all I found.
There was a 70 Formula Ram3 4spd Performance Axle , HD Radiator car that I have a Bsheet for , but evidently never posted it on here.

Wanted to check its radiator code to see if it was also FP , or maybe FS ?

I'm sure others have a copy of it too.
Was a PY members unfinished project that sold on eBay years ago - if that rings any bells.
The Bsheet was posted on eBay , and maybe someone else posted it on here at that time.
The car was discussed while it was on eBay.

Or maybe FS was 3 core Manual . idunno

['ol Pinion head]

Originally Posted by Ramairnacho

Here is a tag pic of one I got. Is it possible to.turn it into an FS?

Ignacio, the only difference in the FS & the FX rads is the core designator, that's what the 91 & 101 number are.

Originally, GM's Harrison division engineered a few near exact same 3 & 4 core radiators with the same 3 core tanks & rails (OR the same 4 core tanks & rails), then specified a different tube /fin count design radiator core between the two radiators. That's what you are seeing here with the '70 F-body FS and FX auto coded 4 core radiators. There are other examples of this, '69 BBC Chevelle SS/Elco's had two different tagged 3 core rads, both the only difference was the core designs.

Today, when you take your original Harrison radiator into a reputable radiator shop, the shop owner can pressure test & either rod it out, or carefully replace the original core with a replacement core. There is not near as much of a selection of original tube/fun count cores today, so you are basically at the mercy of the shop owner to order a core that is close in design, & then install it. Expect $700 & up for the job, & thats if your tanks are very nice, not banged up, needing extra cost metal-finishing or replacement. As always, be protective of the original tags.

[johnta1]

Wanted to check its radiator code to see if it was also FP , or maybe FS ?

FP if this one

[Baron Von Zeppelin]

Thanks for checking John , but that is the same Bsheet I was referencing from above with -
70 WS 4spd AC. (3.31 axle)

The one I am looking for was (70 Formula)
WS
4spd
Non AC
3.73 axle
HD Cooling / Rad
Believe it was one of the Gold colors on exterior

You probably have it somewhere in your files ... possibly.
Mine are all currently trapped except for what are in my PY attachments archive on here.

[Baron Von Zeppelin]

I should have posted/linked those Bsheets I was referencing as I found them.
A little late now.

[Formulabruce]

Just had a 1970 4 core radiator rebuilt. Done right.. cost
$ 965 Dollars. No shipping there, I went and picked it up.
Of note, and I don't know why, All of the 1970 400 cu in ESPRIT's I have seen have/ had HD cooling, AC, and of course a 4 core auto radiator FX. All are Norwood cars, sold in CA. San Raphael, Stockton, Oakland, Santa Cruz. None had the top core support filler panel for improved cooling which is Odd but Dealers had them in stock free under warranty

[Baron Von Zeppelin]

The YS Auto reference was a Formula
The YZ Auto AC was a TA
The WS 4spd AC was a Formula (posted by John)

All were Van Nuys cars.

Even a 70 WS/WT car Non-AC , Non-Performance Axle , Bsheet would be of benefit too.

[Ramairnacho]

Ok so fs is standard 4 row radiation with slightly less fins than the fx 4 row radiator. And fx is a HD radiator found standard in esprit 40o's with ac. Could I get an option HD radiator in a ta or ho formuka? And if so would it be a fx? I have read some guys got optioned HD radiators but not sure what it was. I'm learning and I appreciate all the input.

[Baron Von Zeppelin]

The 400 powered AC cars included HD Rad/Cooling and Clutched Fan as standard equipment in the AC package.
There would not have been a higher level of cooling optional - it was already equipped with it.

Non-AC cars had the option for HD Rad/Cooling that made them equal content as an AC car.

Formulabruce was only commenting on some Espirit cars he had encountered.
And that they all had AC coincidentally.
The same radiators applied to any 70 Espirit , Formula , TA with AC & Automatic.

According to oPh , FS or FX was an either/or supplier variant for the same application.

Your Espirit Auto with AC - and the 70 TA Auto with AC that I referenced - were both supplied with FX radiators.
See the connection

FX is correct for your Ram3 Auto AC Formula
And there is no upgrade above that