dual valve springs
 

Considering replacing 1.677 manley triple springs to lighter 1.5 dual springs for my super stock 520 heads. Installed height is right at 2.050 and could get it to 2" if needed. Looking for recommendations regarding PAC's, Manley, comp or others. Understanding every application is different, how many runs can one expect from the dual springs and how are the springs holding up? Wanting if possible something that would last longer than 35-40 runs.

Ed

Re: dual valve springs
 

#1356 PACs, dual 1.5" diameter. Last all year on mine. Mine set up at 2.1", I have Victory retainers that are std, +.050" &. -.050" hight. I use .200" long valves, the -.050" retainers get away from rubbing my rockers.

Re: dual valve springs
 

thanks Ed. I was really leaning towards the PAC springs (1330 and 1356). I had thought more about the PAC 1330 spring as I don't have as much lift on my 283 (under .850). Still trying to keep coil bind close to .100. I can play with the keepers,/retainers and get installed ht close to 2.0 and end up with about 314 on seat. I too will have to deal with some .200 valves and rocker arm clearance.

Ed

Re: dual valve springs
 

Which Manley spring have you been using?

Re: dual valve springs
 

Jody, it's a set of heads I bought used prep by layer. The spring currently on heads are the manley nextek 221447 spring. spec (350# at 2.0 installed ht.)

Ed

Re: dual valve springs
 

Ed,

We have one engine with the PAC 1.5 springs. They have held up real good Lift is just over .800 at the valve. Installed at 2.100 we get about 350 on a new set. If your spring seats are cut for the triple springs you will need their spring positioners to keep the spring located properly to the guide. we had a learning curve on that.

Re: dual valve springs
 

Mike, thanks for the confirmation on locators. I suspected that would be the case.

Ed

Re: dual valve springs
 

And you're only getting 35-40 runs out of the Nexteks?

I was told by a reputable Class engine builder that some have had problems with the doubles.

Re: dual valve springs
 

No Jody, I have only heard good things from the nexteks in respect to durability. I'm in the middle of a re-build project and bought the used heads with springs already on them. I thought I would look at losing some weight on the valve side before final assembly. My comment regarding 35-40 runs was I did not want to install dual springs and have to have to replace after only 35-40 runs.

Ed

Re: dual valve springs
 

I don't see you having a problem with the PAC dual springs. I have four sets that have a full season on them that still check OK.