wallyj

Hello all,

In reading up on the vortec head swap on my goodwrench 350 most people reccomended machining to the heads or valve seal mods for higher lift cams. I spoke to my local gearhead machinist who has considerable knowledge and he indicated that my .454 lift cam (at .50) will not be a problem, and he said to run them straight, he would be more concerned when lift gets closer to .5 or so.

I like this information, but I thought I would pass it by anyone who may have done a similar swap. Mine is a daily driver, and will have a Edelbrock performer intake, so I am positive I won't be running it hard all the time.. Although I'm looking forward to more bottom end.

Any checks I can do myself? Is it coil bind or valve seal clearance? Should I just upgrade the valve seals and leave it at that?

Any info is appreceated!

Thanks!

ZONES89RS

iTrader: (2)

Yea, anybody that knows chevy engines will tell you that .470 is about the max lift without machine work.

five7kid

iTrader: (14)

However, 0.454" lift is more than stock Vortec valve springs can handle.

Plan on upgrading the valve springs one way or the other.

There is one check you can do yourself if you have a way to remove the valve springs and a way to make precision measurements. Remove the valve spring and put the retainer and keepers back on. Hold the valve closed against the seat by pulling up on the retainer and measure the distance between where the spring seats on the head and where the spring seats on the retainer (you need to be able to measure this to 0.001") and write it down. Open the valve until the retainer hits the top of the valve stem guide seal, and measure the distance between the spring seat and retainer again, subtract this number from the first number. That is your valve travel. Now subtract an additional 0.060" - that is your safe "valve lift". Repeat for the other 15 valves. If any are under 0.454" (assuming you have the same lift on intake and exhaust), you don't have enough valve travel to use a 0.454" lift cam.

ZONES89RS

iTrader: (2)

LT1 springs locks and retainers should fit the bill.

wallyj

Ok well then, should I locate some used LT1 springs and retainers or look for the easiest supplier of new springs? Are you using LT1 Springs in a similar setup?

jmat2407

iTrader: (-1)

If your upgrading the springs but don't want to do any machine work go with a set of beehive springs. They'll allow mid .500" lift without any machine work.

ZONES89RS

iTrader: (2)

Nope, i always have mine done at the machine shop, i usually never run a cam under 500 lift.

vetteoz

iTrader: (13)

https://www.thirdgen.org/forums/tech...ortec-lt4.html

wallyj

I'm trying to avoid extra machining costs, are there springs, retainers, locks that work with the valve seals that anyone could recommend for my small cam? I have done a few searches on summit racing but nothing seems clear enough there and you seem to already need to know what you need because the tech dept hasn't helped me yet

There must be someone who has a drop in spring kit without machining I can use! Calling all part numbers!!