alright so far what i have is a 350 4bolt main with and edelbrock torker cam (.488 lift) from my previous build. im taking off my WP sportsman II heads and putting in vortech heads. The vortech stock from what ive read only accept around .430 lift so im thinking ill have to get the valve guides machined down so i can keep my cam unless anyone has a easier way of getting these heads to accept more lift? Im putting an edelbrock preformer RPM intake on along with a 670cfm holley carb with vac secondaries and an electric choke if i can find one for a decent price. this is a conversion build from my tpi setup and ive never worked carbs before so any opinions or advice would be nice, thanks.

 

Typical Vortec lift capability is around 0.470-0.480" lift, although there have been reports of only 0.430" capability. You can either use beehive springs, which put the retainer farther up the valve stem, or have the top of the guides cut. If you cut the guides for positive-type stem seals, you'll not only increase the valve travel capability, but have a better valve seal as well. Regardless, you need better than stock Vortec valve springs.

Any particular reason to go with a vacuum secondary carb? It may be okay, but probably not as good as a double pumper would be. Don't fall for that old "vacuum secondaries with automatic transmission" yarn.

 

from what i hear double pumpers are more for drag strip use ill be street/strip whats the difference as far as preformance? and any recommendation on what springs i should get?

 

For me, the difference going from VS to DP on the track was 2 tenths, and when you let off the accelerator, the throttle blades actually close (kind of a nice feature).

You don't want a VS carb for street/strip.

 

alright ill look into a double pumper then. im taking these heads apart now to get the valve guides cut down. and i do have a set of sportsman II heads laying around now is there any reason why i cant use those valve springs?

 

The Vortec guides are too fat to allow a lot of performance springs to fit over them. Check if the Sportsman II springs fit over the guide - if they do, you should be able to use them.

 

You could use LT4 springs and you might not need the guides cut if you check space between guide and retainer and you use 1.5 rockers.

 

well i still gotta machine the valve guides down for the lift anyways might as well have them do both while they are in there.