speedtigger

iTrader: (16)

Anybody know the intake and exhaust valve drop measurements on TSP PRC Stage 1 CNC LS6 heads?

mikesimpalass

Are you talking about testing piston to valve clearence? If so, you want at least .080 on the intake valve and .100 on the exhaust valve

Always2Slow

iTrader: (8)

He wants to know how recessed the valve job is in the head. I would imagine it would depend on the core used because texas-speed will cnc your heads or use one of their cores.

speedtigger

iTrader: (16)

I guess nobody else measured theirs either? LOL
I asked Texas Speed, but just the salesmen was there when I called. The guy said he thinks they have about .020" more than stock.

Anyone measure the valve drop on stock 243/799 heads?

speedtigger

iTrader: (16)

Well, I decided to just go measure my assembled valve drop. It was .194" Intake, .206" Exhaust. So, I am thinking the valves are not sunken .020" like the TSP salesman suggested.

Nwayne

iTrader: (3)

Did you find out what stock is?

speedtigger

iTrader: (16)

There is actually very little I could find posted. Of the few posts that I did find, I think cathedral port stuff is .155" intake head only and .165" exhaust head only. .200 intake assembled and .210 exhaust assembled withe a factory MLS gasket and ls1/ls2 type flat top pistons. I wish measured my old stock 317s before I sold them.

What is surprising to me is how many threads there are about "how much cam and will fit", yet so few measuring this.

Nwayne

iTrader: (3)

I'm surprised too. When I started talking to Kip at cam motion that's one of the things he asked me. I didn't want to pull my stock 243 heads so I was searching everywhere for the info.
Thanks for posting this stuff!

speedtigger

iTrader: (16)

You don't have to pull the heads to do an assembled valve drop.

Just pressurize the cylinder with 100+ PSI of air using your compression tester hose hooked to your air compressor, removed the valve springs, put a couple rubber bands on those valve stems to stop the valves from falling in the cylinder when you let the pressure out of the cylinder, put that cylinder at top dead center and then let the valves down until they rest on the pistons. Measure the distance from fully closed, to where they rest on the piston. That is your assembled or "actual" valve drop.

This is what I did last night. It took me about an hour and a half to do the whole deal including putting it back together. But, my car is a lot easier to access everything than most guy's fourth gen Camaros. It should be easy on your Nova too.

JakeFusion

iTrader: (7)

Stock valve drop is ~.155"-.160" on LS6 heads. So if you have more, they've recessed the valves.

speedtigger

iTrader: (16)

Have you measured a set of unmolested 243/799s? How much difference did you see between intake and exhaust?

JakeFusion

iTrader: (7)

As far as I remember they should be about the same.