Well to do a bit bench racing for you, your 7.32@95.3 1/8th is approx an 11.6@118 1/4. I am having to guess the weight of your car at 3800 with you in it? so that gives you currently 511fly hp with those 906 heads.

Bolting on those sidewinders at 84cc will drop your comp a bit if you don't mill them to 79cc but no matter, if they really flow 290cfm I would think conservatively you would get around an 80hp increase over stock 906's which should give you 590 fly hp, that in a 3800lb car should run around 6.80@100mph in the 1/8th, or 10.84@124 in the 1/4. Only numbers but the Wallace Calc has been pretty accurate for my cars against my 1/4 mile timeslips. Good luck with it.

I'm still impressed with how well it ran with stock 906s

Actually, he said they were "cleaned up a bit", and have 2.14/1.81 valves....... So, not "stock".

I think I'll stay with the cam and mill the heads a little to get them down to 78cc (similar to my 906's) so it will be very interesting to see how much just the heads do.
I have talked to a friends friend with a flow bench and he's interested to see how much we can improve the heads with some work. I have already ported one head on the exhaust side but we can compare it with the unported. My problem is to find the time to go there since he is three hours away...
Thanks for your help!

I would stay with the cam in it, mill the heads a few CC smaller than the 906s and let it eat. With aluminum heads and tight quench it will be fine on 93 or so octane. If you need more later than send the converter out for a little more stall. With the much better flowing heads you will need to bump up the shift point but you shouldn't lose much if any down low. 50# off the front will help the 60 FT.

I don't have any idea what the motor made before, but something around 500hp certainly seems about right for that combo.
Sidewinders don't flow 290cfm ootb, but can pretty easily without too much work.
Although, even with them flowing 290, that combo on our dyno would be very hard pressed to make 590hp.
I've built and dynoed several stock stroke 440's over the years that approached(or exceeded) the 600hp mark, and they all had quite a bit more duration than the OP's cam.
Depending on just how good the heads end up being, and what the final CR is, I'd say more like the 560hp range is more realistic.
Which....... If the car was set up properly, would get it into the 10's.

As usual I end up working with my cars some months too late...
Finally I am in the process of shaving the heads to get the CR up. After reading your comments I think getting close to 76cc would be safe.
My question is if the first .010 you shave off the volume decreases with appr. 2.5cc, how much does the next .010 affect cc?
Help, I need the formula

Roughly, .006" removed per cc

I followed your advice, stayed with the cam and milled the new heads to 11,55:1
Made a few 1/8 passes yesterday and engine runs like a dream BUT now the converter stalls 5,600 rpms!
Could not shift fast enough, was hitting rev stop so I raised it from 6,300 to 6,800 (stock rods) but was a half second slower, no traction (1,9-ish 60-ft) but same speed. Was confused... Stopped, put in third gear, foot hard on brake and then gas pedal down while I looked on tach. Couldn't hold the car still, front runners was sliding. Did it four times and same result, tach did stop at 5,600 every time.
How is this possible?
Do I need a new converter? Or can it be modified? What should I look for?

If it's an 8" converter(which is what I think you said it was), then that's about where it would stall.
It can be tightened up, but I think in the long run you'd be better off leaving it as is and installing a longer duration cam( and aftermarket rods).

The 8" behind my 383 stalled 5400...... And it worked great!!

I'd start working on sorting out the 60' issue...... Less stall won't really "fix" whatever the problem is there.

I guess you're right. It's time to look over and go through the 440 anyway. It deserves better rods and by then a hotter cam would be interesting.