How far to trust LS 5.3 OEM valves?

[PackardV8]

Since the Studebaker V8 heads are flow-limited, no current generation cam cores, few available intake choices, most builds are relatively low horsepower. For this particular build, the 7mm would be an option.

[tt 383]

Now I feel old. I thought LS1s were still common.

For true. When I started using the 1.890" 4.8/5.3 LS valves and springs in Studebaker V8s, they were the latest and greatest. By 2007, they were obsolete and now difficult to find.

A bit of trivia - in my search for the valves, I turned up an old test of four different OEM LS heads on 5.3s. They made much of the shocking result. The original 1.890" valve heads made more horsepower than any of the 2.00" intake heads.

Wasn't the chamber size like .150 bigger than the 3.78bore for those other heads? Throw in small difference of compression, larger runner volume. Wonder if they notched the top if the cylinder how the 799 would have done being it was so close. O also think it Interesting they switched to that 243/799 style head in the later models.
A little more on topic, can u utilize the ls9 exhaust valves?

[Keith Morganstein]

"Back when LS1s were common"

Now I feel old. I thought LS1s were still common. I guess I'll stick to my stone-age Gen 1 SBCs.... can't keep up with all this new-fangled technology. LOL

They made "SBC"s for thirty or fifty years depending on who you ask, they only made LS1s for five or six years.

How common are DZ302s or LT-1s?

FWIW the OP’s talking about LM7 valves, LM7 is a 5.3 made from 1999 to 2007. 1.890” intake valve... (not LS1 with 2.000” valve)

On the LM7 I haven’t seen any of the 1.890” intakes fail, but I see high mile ones I don’t want to re-grind because the valve heads are pitted up. Usually the stems are still in good condition. OTOH, the aftermarket replacement valves are not nearly what the OEM is. The valve head shape is different, the chrome stems have a worse and rougher finish and the chrome seems softer.

I looked and the OEM valve has gone up in price to over $18 ea. That’s getting close to a custom Ferrea from Brian B.
I asked Jack how much he’s getting them for...but no response.

[PackardV8]

FWIW the OP’s talking about LM7 valves, LM7 is a 5.3 made from 1999 to 2007. 1.890” intake valve... (not LS1 with 2.000” valve)

On the LM7 I haven’t seen any of the 1.890” intakes fail, but I see high mile ones I don’t want to re-grind because the valve heads are pitted up. Usually the stems are still in good condition. OTOH, the aftermarket replacement valves are not nearly what the OEM is. The valve head shape is different, the chrome stems have a worse and rougher finish and the chrome seems softer.

Thanks, Keith; that's what I had suspected. Any brands to avoid? Yes, these days with random reboxing, we don't always get the same supplier in an Enginetech box twice in a row.

I looked and the OEM valve has gone up in price to over $18 ea. That’s getting close to a custom Ferrea from Brian B. I asked Jack how much he’s getting them for...but no response.

For the milder builds, we began using cut down OEM intakes and standard exhaust, as pulled from new heads. When those were gone, we've been using Enginetech and paying about $8 each. This is the highest RPM Stude we've ever built and it has a high-dollar roller valve train. Not a place to skimp on valve quality.

[Keith Morganstein]

FWIW the OP’s talking about LM7 valves, LM7 is a 5.3 made from 1999 to 2007. 1.890” intake valve... (not LS1 with 2.000” valve)

On the LM7 I haven’t seen any of the 1.890” intakes fail, but I see high mile ones I don’t want to re-grind because the valve heads are pitted up. Usually the stems are still in good condition. OTOH, the aftermarket replacement valves are not nearly what the OEM is. The valve head shape is different, the chrome stems have a worse and rougher finish and the chrome seems softer.

Thanks, Keith; that's what I had suspected. Any brands to avoid? Yes, these days with random reboxing, we don't always get the same supplier in an Enginetech box twice in a row.

I looked and the OEM valve has gone up in price to over $18 ea. That’s getting close to a custom Ferrea from Brian B. I asked Jack how much he’s getting them for...but no response.

For the milder builds, we began using cut down OEM intakes and standard exhaust, as pulled from new heads. When those were gone, we've been using Enginetech and paying about $8 each. This is the highest RPM Stude we've ever built and it has a high-dollar roller valve train. Not a place to skimp on valve quality.

I’m not that happy with anything from qualcast or SBI in that valve.
Take a look a SI valves SEV-01934 1.890 intake valve. I’m going try a set on the next one.

EB94480C-FA86-44F6-A0DC-E43A9426B26F.jpeg

[PackardV8]

Hi, Keith,

Thanks for the tip. I just ordered a set from SI. It will be interesting to compare with SBI as to quality, because SBI prices aren't that much less than SI.

[pdq67]

FWIW the OP’s talking about LM7 valves, LM7 is a 5.3 made from 1999 to 2007. 1.890” intake valve... (not LS1 with 2.000” valve)

On the LM7 I haven’t seen any of the 1.890” intakes fail, but I see high mile ones I don’t want to re-grind because the valve heads are pitted up. Usually the stems are still in good condition. OTOH, the aftermarket replacement valves are not nearly what the OEM is. The valve head shape is different, the chrome stems have a worse and rougher finish and the chrome seems softer.

Thanks, Keith; that's what I had suspected. Any brands to avoid? Yes, these days with random reboxing, we don't always get the same supplier in an Enginetech box twice in a row.

I looked and the OEM valve has gone up in price to over $18 ea. That’s getting close to a custom Ferrea from Brian B. I asked Jack how much he’s getting them for...but no response.

For the milder builds, we began using cut down OEM intakes and standard exhaust, as pulled from new heads. When those were gone, we've been using Enginetech and paying about $8 each. This is the highest RPM Stude we've ever built and it has a high-dollar roller valve train. Not a place to skimp on valve quality.

Jack,

What is the rpm limit of a stock '51 232" Stude Commander V-8 with an automatic on the back? (4-dr car)...

I ask because Jerry used to run the living dog-sh*t out of his late at night on the Hwy's between our small country towns back then. AND back then, there weren't any cars on the Hwy's late at night on the week-ends! So off we'd go, wide open!

pdq67