Gen VI 454 max valve lift?

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Gen VI 454 max valve lift?

Post by 74wagon on Sun Jan 13, 2019 11:39 am

So I'm running a Gen V 454 in my wagon but I found a set of Vortec heads at the wrecking yard yesterday. I grabbed the roller lifters and pushrods as well. My wagon is incredibly budget minded, but I'd still like a little bigger cam. Does anyone know for sure what the max valve lift the stock springs can handle? I'm not looking to rev it to the moon. I like to stay below 4500. It's a daily driver that gets stomped on from time to time. So my cam choice I'd probably max the lift at .520 I'm thinking.

Thanks in advance folks.

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Re: Gen VI 454 max valve lift?

Post by fasrnur on Sun Jan 13, 2019 12:45 pm

My advise would be to deal with the cam companies directly. Check with more than one and se what they all say. They are there to sell cams and most of them know their stuff. Not saying people here don't know what they're talking about, but to say what cam will be the best for your car is a science. Heads, comp, intake, convertor, gears, how you use it all plays into what cam is best for you sir.
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Re: Gen VI 454 max valve lift?

Post by 74wagon on Sun Jan 13, 2019 2:36 pm

Very valid point. Thank you. That's what I'll do.

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Re: Gen VI 454 max valve lift?

Post by bracketchev1221 on Sun Jan 13, 2019 5:32 pm

Measure the installed height of the spring and then remove one and have it checked by a machine shop. Without having actual spring pressures it’s all guesses. Your springs might be worn out.
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Re: Gen VI 454 max valve lift?

Post by REVINKEVIN on Sun Jan 13, 2019 6:37 pm

Hey. I think you will be a little ahead if you save a little more and get the cam and spring kit. I know it's a little more money but the old stock springs aren't going to like much cam at all.
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Re: Gen VI 454 max valve lift?

Post by Iggy on Tue Jan 15, 2019 11:48 am

The Gen VI Vortec Heads do not flow much past .500" lift so anything beyond .530" - .540" is a will not do you much good.  Comp Cams limits their cams for the Vortec head to .510".  Physically the heads can handle .600 lift, they just do not flow much more with that higher lift.  As for springs, use the ones recommended for the cam you are using - GM big block stock valve springs are notorious for being too weak for higher lift cams!  Also keep in mind when changing valve springs on Gen VI heads you also need to remove the rotators that are on BOTH INTAKE and EXHAUST and replace the with spacers.

Gen VI heads are a very nice torque head and the exhaust port flows better than the Mark IV oval or rectangular port heads, so when you choose a cam you want one with only about 5* more curation on the exhaust as the exhaust flow is better matched to the intake flow than the earlier heads.
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