The Project

iTrader: (6)

I was looking at swapping the stock cam in my 89 305 TPI for an LT1 cam. The LT1 cam has a .450" lift.

Will the stock springs on the 305 heads handle this?

What is the lift on a stock 305 spring?

Thanks...........Bill

Auggie

Maybe someone else can give you the exact answer but I have 305's heads on my 355 and the cam lift is .470" with the stock 305 L69 (shimed) springs.

Auggie

1991CamaroRslow

iTrader: (3)

They may handle it but there's absolutly no point in putting those springs back in when you're already in there swapping the cam. Just buy a set of the Elgin/Pioneer ".550" max lift springs, even the ".500" max lift springs will work.

kairles

iTrader: (2)

I read some where that the adverage stock spring can handle about .490" lift

Damon

The stock springs on most SBC heads can easily handle .500 lift BUT.... they lack the pressures necessary to control anything like a "performance" cam. They're marginal even for a stock cam.

The REAL limit on stock heads is that the retainers typically hit the guides/seals around .470" lift. So you need to stay under that unless you do some machine work to the heads, regardless of what springs you put in it.

Comp 981 springs are a nice upgrade over stock and drop in place of stock without any machine work to the heads. I've used them successfully with both performance flat tappet cams and mild hydraulic roller cams, like the LT1 cam you're considering.

The Project

iTrader: (6)

Thanks...........I will be putting in a 355 or 383 in a few years and will buy decent heads with good springs on them.

This is why I didn't want to buy springs now, as it seems like a waste of money. If I can get away with the stock springs with the LT1 cam then I am ahead of the game.

Kevin91Z

iTrader: (1)

The problem with that is the stock springs are now 15+ years old and have been subjected to a million cycles at .430" lift. You are now going to make them run at .450" lift. Its your call, but springs wear out after 5-10 years.