A good starting point for valve spring requirements is with your cam specifications. Make sure your valve springs meet the cam requirements. I interpret 0-5500 rpm as the "breathing range" for your heads. Air simply will not flow well above this range. If you truly intend to regularly operate your engine above 5500 RPM, these heads are not your best bet.

Since you have a lot of parts already, build what you have knowing your operating range is up to 5500 RPM. No need to spend mega-bucks on exotic stuff to rev to 7000 RPM. Your heads are your limiting factor. I have E7 factory iron heads that I gasket matched/ported myself. You are already a step up having aluminum heads. My cam is from Summit Racing, 0-5500 RPM It is a SUM-4400, same grind specs as Edelbrock performer. The engine will get a cam and heads upgrade, but not right now. I love driving my (hand built by me) car. 

Last edited by hanxno (2/26/2014 8:54 PM)

So what is the suggestion?? I read on a forum that K-Motion K750 is a good drop in replacement for the E-street, this really confuse me, Edellbrock website indicated 1.460 spring diameter while K-Motion K750 has 1.265 diameter....What spring will drop in nicely as a stronger replacement for my E-Street???

Tmac wrote:

I have those heads on my 289. K750 was the part number I got for better springs. Had a cam that had .512 lift on intake and exhaust. Limit for the springs that come on the heads states .550 max. So instead if changing the springs. I bought a different cam. Toned down. But the engine runs strong and I like it.

So you did not buy the K750 and currently still running stock spring? Do you ever get past 5500rpm?
 

Back last year  CC mag did a budget head comparison and the E streets were pretty high on the list as a good performance head for the price.  I think Trick Flow just beat them out for the HP but not in price.  Steve69

Above is the camshaft specs...really mild cam but it is what I have in hand....Should I go 1.6 or 1.7 rocker ratio for a street friendly setup?

I don't know about your Edelbrock combo, but two years ago I had a problem with loss of power at about 4500-5000 rpm when I installed some 1997 5.0L GT-40 heads on my 351W. I put it on a dyno and the techs said valve float was my problem. The stock GT-40 valve springs did not match up with the Comp Cams XE256H-10 cam that was in my engine. It was originally matched with a stock set of 70 351W heads. The machinist that put the engine together originally said he had seen that before, and he suggested going with some Comp Cams 942-16 and 901-16 replacement springs. I swapped them out with the GT-40 springs, and problem solved - goes  right through 5000 without skipping a beat.