Cal

iTrader: (1)

My wife's LT1 TA needs new valve springs, and I have my nearly new stock "take off" LS1 springs and retainers sitting here. Looks like they would fit except the spring seat washer is a little too big. Has anyone tried using the LS1 spring seats and springs on a LT1 head? I don't want to order the LS1 spring seats unless they will work.

94Formula/TA

I would contact someone at SLP and see what they think. They say that the springs they sell for the LS1 can be used on LT-1 applications, so I would ask about your stock springs.

Cal

iTrader: (1)

Thanks 94Formula/TA; interesting what SLP says. I've decided to go ahead and do it. The LS1 spring shims were cheap and they fit with a slight enlargening of the ID (hole.) I'm boring the holes bigger on my lathe with a carbide tipped boring bar. The washers were too hard to drill out. I'm just waiting for the GM parts counter to get me enough of them to do the whole engine.

ChrisB

You may have an issue with the retainers/locks and the valve tip - I think the ls1 uses a narrower valve?

modernjeff

you can use the springs,, withe the seats opened up to .555 i believe,, but you cant use the stock retainers,, you have to get the comp retainers #787-16,, ls1's have a 8mm valve stem,, lt-1's have 11/32,with a 7 degree lock/retainer combo,, that system is respective to the stem diameter of the valve

jeff
modern cylinder head

mingoman

Modernjeff is right.

I have researched the issue as well.
Might wanna order some good lt-1 specific springs to save the hassle. there are plenty of good springs out there .

Cal

iTrader: (1)

Well so far I have picked up a set of LS1 seat shims from the dealer, which I opened up to the same ID as the LT1 shims, using my lathe to machine out about 30 thousandths from each one. After having done that, using LS1 retainers and LT1 keys, the LS1 springs fit fine even though the LT1 valve stems are slightly larger than the LS1 stems. The LT1 stems were actually smaller than 11/32 on this car. When I get the heads back on the car, I'll post the results.

LS1 SPEED INC.

iTrader: (1)

Here are the Comp part numbers:
-CC26918 COMP OVATE WIRE SPRINGS
-CC787-16 COMP STD. 7* RETAINER FOR 26915/26918 LS1 SPRING
-CC648-16 COMP 11/32 7* MACHINED STEEL LOCKS
$229.99 total price

Tom
www.ls1speed.com
1866-LS1speed