Sunsceamer

My dad has the 350ci 330hp/380tq vortech crate motor from gm. We are swapping the cams for something loppy. Ihave a set of new hot cam LT4 springs and was wandering if they will work. The springs have vever been used.the cam is the comp 268H.

Damon

Not sure but I can tell you a few things to check. First off, Vortecs are lift limited more by retainer to guide seal clearance than by the springs themselves. If you use that cam, DON'T use 1.6 rockers. It'll hit for sure without having the guides machined down.

Stock Vortec heads will ONLY take 1.25" dimeter single coil spring with NO dampener coil on the inside. There is a large diameter guide boss on the Vortecs that basically locates the bottom of the spring in the spring pocket from the inside of the spring coil. Even a 1.25" diameter spring with a thin, flat dampener inside will not fit over the guide boss without having them machined to a smaller diameter.

I'd also check the installed height of the spring pocket. I'm not sure what LT-4 springs are spec'ed for but you better measure your installed height between the spring pocket and bottom of the retainer before you find out you're shoving a spring spec'ed for 1.75" into a 1.65" installed height.

My limited experience with Vortecs tells me that you can't do much with them before you end up having to get the guides machined in some way or other.

Sunsceamer

Thinks I will end up putting a smaller cam in. I would like to make it lope nice. Not as worried about performance since this engine has never seen above 4200 rpm's since when he gets on it it shifts at that rpm in drive. He just wanted it to lope and I see the 268h is a popular cam. Any suggetions on a cam that will be low lift but tight lobe seperation? I was tolds it was more the lobe sep that made the drastic lope. I will put this one in my truck and buy him another one.

Any suggestions would be good for a loper cam. remeber the car may never see above 4500 rpms since my dad love the but kick it has now and just wants to sound good.

Sunsceamer

Anyone with a suggestion on witch cam?

Damon

If you want her to sound choppy at idle you want to tighten up the LSA. The cam that comes in the crate motor has an LSA of about 112*. That same cam ground on a tighter 106* LSA would make for a modestly rough idle, changing no other specs.

I would think that a cam with about 220-225* duration @ .050 on a 106* LSA and lift not to exceed about .460" would give you the rumble you're looking for. That may not be an off-the-shelf cam becuase most cams with that much duration will typically have too much lift for a stock Vortec head. Might have to spend some time on the phone with the cam companies.

Sunsceamer

thanks

69camroking

isn't a 106 LSA awfully tight for any kind of cam? just wonderin, not saying you're wrong or anything!

AutoRoc

Comp makes some flat tapet grind @ .485 and under for the Cheap Street class. A few wild grind to choose from only limited by the .485" rule. They sound bad ***.