I have a set of EX-612 springs that Combination Motorsports sells, and I wanted to use the GM 847 cam with those springs. They are single-coil springs, and are supposed to handle up to .600" lift. With the GM 847, the lift on the exhaust side is .595". Am I taking a huge risk if I use these springs with the GM 847? I was thinking that the actual lift on the cam wouldn't come close to the advertised maximum lift so I am thinking that I might be fine with those springs. Let me know what you think. Thanks in advance.

 

I would DEFINITELY get a dbl spring set up with that cam. If you have 1.5 rockers with that cam and only want to turn a lil past 6000 RPM, those springs might work "OK" but If you are gonna try and turn the engine until that cam stops pulling (abovr 6500 RPM) you would be MUCH better off with a double spring set up.

If you are in fact using the 1.6 rocker, I would not even consider the single spring.

That spring will handle .600 lift and not coil bind if set up at a specific set up ht. but to get 130 lbs on the seat, you would not wanna use a lift that high.

Give em a call and see if you can send those back and get some dbl springs.

NightTrain66