Ok So I'll Try A More Techinal ? To Peek Interests, Valve Size And Valve Reliefs

So, I'm wanting to go gt40 heads and Im currently running e7's. My cam and piston specs are below however I couldn't find the size of the valve reliefs on the pistons and I couldn't find a site of the manufacture (speed pro) I could only find retailers, summit, jegs, etc. With my cam of .512 lift should do you think I will have ptv issues with the gt40's as where I don't with the e7's or are the gt40 valves that much bigger that I will run into problems? Im ready for the response "one should always measure" before install but I don't want to order a set of heads that most likely will need piston notching since I'll have the car torn apart only to find they are not going to work. It's not like I can run to walmart to exchange em for a different set.... Anyways here are the spces,, thanks for the replies, lately I've only been getting views. Oh and I get it the gt40 head thing has been beat to death but c'mon guys has anything new happened with the 302 in the last 20 years!? Also I think speed pro was bought by china hence the no corporate website. One final question before I let yall go, will springs from an e7 work on the gt40 head? My e7's have better springs than whats offered on the heads and I want to reuse if I can (beehives)
Comp 35-440-8
2000 to 5500 operating range
281HR cam grind number
281 duration in (advertised)
281 duration ex (advertised)
220 duration in @ .050
220 duration ex @ .050
.
512 valve lift in
512 valve lift ex
110* lobe sep angle

Speed-Pro Hypereutectic Pistons ZH120CP30
Bore (in):4.030 in.

Bore (mm):102.362mm

Piston Style:Flat top, with two valve reliefs

Piston Material:Hypereutectic aluminum

Compression Distance (in):1.615 in.

Piston Head Volume (cc):+5.00cc

Wrist Pin Styleress-fit or floating

Pin Diameter (in):0.912 in.

Piston Ring Thickness:1/16 in. x 1/16 in. x 3/16 in.

Dang stangnet.... threads been up 20 min, ten views, no replies.... Where did all the people with the answers go?

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