6.0 silverado

iTrader: (2)

I've done a good amount of searching, but I have not found a definitive answer.

Will the ptv clearance be the same with a set of untouched 243s as a set of untouched 241s? I'm pretty sure it will be the same, but I wanted to confirm.

Paint_It_Black

iTrader: (1)

The 243 will be ever so slightly less, the 243 had a 64.45cc chamber and the 241 had a 66.67cc chamber.

Source:
http://www.smokemup.com/tech/ls1.php

6.0 silverado

iTrader: (2)

So. a smaller chamber equates to less PTV in this case? I know if the heads were milled, the chamber would be smaller and ptv clearance would decrease, but they are different castings.

Paint_It_Black

iTrader: (1)

Yeah, you got me, I'm not sure if there is a valve drop difference.

98z-28redcamaro

iTrader: (3)

243's and a trex will work but i only had 24thousands clearance

Theblacknightls1

iTrader: (1)

Damn Nice tourqe n/a

6.0 silverado

iTrader: (2)

On my current set up with 241's. I have 82 thousandths clearance and I don't want to loose anymore or it will take me out of my confrot zone. 24 thousandths is cutting it pretty close.

02*C5

iTrader: (1)

The_Rizzle

iTrader: (4)

Intake or exhaust?

6.0 silverado

iTrader: (2)

No one knows if my ptv clearance will change with a 243 swap?

itsslow98

iTrader: (18)

what size cam?

1SLwLS1

iTrader: (6)

If it has the solid valves, then no, it will not change. The solid valves should have the same valve drop as the 241s. The chamber is smaller around the sides, not in height. I have heard that the lightweight valves are a little longer and may affect PTV, but since I have not used these, I cannot confirm. The 243/799s with the solid valves, should be exactly the same.

The_Rizzle

iTrader: (4)

the valves would be longer on the spring side of the head, not inside the chamber. I have both sitting in my shop, I'll take a look.

I'm going to say that the PTV should stay the same, as the chamber is smaller on the spark plug side, and starts to create a 2nd squish pad. Which leads me to believe that the valve clearance will be the same. However, I will double check.

6.0 silverado

iTrader: (2)

it is a 230/234 .600/.602 111+4 on eps lobes


I really appreciate it. I thought this would be common knowledge since this is such a common swap.

1SLwLS1

iTrader: (6)

I was unsure if the stem was longer, which would indicate as you said, longer outside the head, or maybe the valve was a little thicker, indicating a longer OAL. I am interested as well if you have both sitting in your shop.

The_Rizzle

iTrader: (4)

The only reason the ls6 (hollow/sodium) valve is longer is to make up for the smaller base circle cam, and since the installed height is the same, its only the tip they lengthened.

Anyways, I just weighted one of the 243 intakes, its not a lightweight one, so I have no way to accurately verify the above, however, I'm pretty sure I'm right.

Back to the original question of 241/243 PTV clearance, They are the exact same, stock for stock. Any valve work with stock valves should give you a tiny bit more, any milling will reduce your PTV by the same amount as milled.

This I just verified ^^^

Yeroon

Theblacknightls1

iTrader: (1)

Nice t/a btw

1SLwLS1

iTrader: (6)

Thanks! Guess I have to change my S/N since its not an LS1 anymore, huh?

6.0 silverado

iTrader: (2)

That's what I figured. Thank you VERY much.

Busy Mopper

iTrader: (4)

This is your best answer!