is the action on the Winchester Model 70 safari express longer than a 30-06 action ?

No; all post 64 Model 70s are H&H mag length. Only the mag boxes and bolt stops are different, and maybe some bridge relief but the receivers are all the same length.I don't count the short actions. WSM etc.
I routinely take 30-06 rifles and make 375s of them and put them into Safari Mag stocks; I have like 6 of them. Those stocks are cheap now.

thank you
I wish we would have good gunsmith over her in Canada
my dream is to have a Winchester Model 70 extreme in 458
up to now I had 3 Winchester Model 70 in 458
one Ruger No 1 in 458
one Ruger 77 in 458
no I have a Sako brown bear in 450 Rigby
and thinking seriously change to the model 70 safari express

The ejection port is opened to the rear as well. Thus the .330 screw spacing on the rear bridge.

Right, when I convert one to 375, I leave the bridge as is; it still works. Cut off the bolt stop...

The action lenghts are indeed the same on the post 64 Model 70s. The difference is the ejection port.

On my LH 375 H&H Safari Express the ejection port measures 3.380 on my LH 30/06 Model 70 the ejection port measures 3.120.

If you want to use the longer 375 H&H length cases in the non Safari Express action you can but you'll need to slip the loaded round in nose first when you charge the magazine.

I alway wonder why the .330 screw spacing on the rear of the receiver
now I know