rhino200099

iTrader: (1)

Does anyone know if Ls3 springs will drop into 243 heads with 243 stock retainers.

SS69LS1

iTrader: (108)

Yes they will. I just transferred the springs from my 243 heads to LS3 heads.

96capricemgr

iTrader: (1)

I thought the LS3 despite hollow valves was know to break a spring now and again.

KW Baraka

iTrader: (7)

I only know that I just couldn't wait to get my stroker engine installed. The stock rockers and valve springs were a big part of the reason why.

KW

rhino200099

iTrader: (1)

im just going to run an l99 cam in a lc9 5.3l. want to make sure everything will work ok

KW Baraka

iTrader: (7)

I still wouldn't run those springs.

Like Dwayne mentioned....they break, even with stock cam and valves......

KW

96capricemgr

iTrader: (1)

Smaller engine will need more rpm and you probably have solid valves which will need more spring. Bad idea.

rhino200099

iTrader: (1)

will stock 243 springs be ok?

KW Baraka

iTrader: (7)

If it were my engine, I'd run these --->> https://www.racingsprings.com/1200-S...-1218/Item/206

KW

96capricemgr

iTrader: (1)

Have you done any research that indicates it is a good idea to use an L99 cam.

What I have found
Vs.
LC9 Camshaft Lift (in.):
.467 intake / .479 exhaust
Camshaft Duration (@.050 in.):
196° intake / 201° exhaust


If those numbers are correct and figuring the L99 cam is meant for use with VVT and rectangle port heads I would call this swap misguided, wouldn't do it with free parts.

rhino200099

iTrader: (1)

ive heard this is common swap. ill be doing a vvt delete to go into a 09 lh6 truck. parts are cheap and I have a free lc9 with a bad cam. I do have an ls3 cam but I would have to do a afm delete as well. kinda exspensive to do. I thought this would be a good alternative. what do you think caprice?

96capricemgr

iTrader: (1)

I have heard of the LQ9 cam being used in 5.3s.