Better quality small intake valves for SBC and/or 5.3 LS?

[PackardV8]

Back story:

We bought several sets of new take-out LS valves, springs, retainers and locks and have been using them in mild performance applications in the Studebaker V8. The reason they were available is one of the members here builds custom LS heads, using higher quality valves and springs. At what RPM range are OEM LS valves likely to be the failure point?

A customer wants a Stude built for vintage racing, so turning higher RPMs for longer periods. It seems most Chevy racers upgrade to the larger 1.94" or 2.020" intakes, so there aren't as many choices in the 1.840"-1.890" diameters. What are the better high performance catalog valves in 305" SBC and 5.3 LS? Where would you go to order valves and springs?

Bonus questions:

1. Yes, it depends on the cam lobe profile, but what seat pressure would you choose for extended 6,000 - 6,500 RPM, given these are smaller valves?

2. The Stude V8 uses an 11" long but fairly strong pushrod. What diameter/wall would you choose if ordering custom pushrods?

3. We like the beehive springs for street/light strip duty, but are they to be trusted in endurance racing applications? Would you go with dual cylindrical springs for this build?

[Frankshaft]

A 2.0 inch intake fits the 5.3 bore well. A 1.6 ex valve will hit though, so just use a good quality 2.0 intake valve from your valve supplier of choice, and a stock exhaust size. One of the best bang for the buck valve spring kits is from TFS, you can buy them thru Summit. Quality dual springs, they have 2 choices, titanium retainers, spring id locators, machined keepers and viton seals. About $300. Hard to beat. Ti retainers from some sources are almost that much. I have used many of those kits and have had no issues. Road race, drag race and street with no issues. They have a 140 seat, and 380 open, and 150/400 open choice. Pac has similar kits, for similar price, but they come with steel retainers. As an example, with ti retainers in the PAC kit, it's $475 for the equivalent parts.

[PackardV8]

Thanks for the suggestions.

The GM LS 5.3 has a 3.78 (96mm) bore, but the Studebaker V8 is only 3.625" (92mm), so we're pretty much limited to 1.875" max valve diameter and on higher lift cams, even that requires notching the top of the cylinders.

[Frankshaft]

Thanks for the suggestions.

The GM LS 5.3 has a 3.78 (96mm) bore, but the Studebaker V8 is only 3.625" (92mm), so we're pretty much limited to 1.875" max valve diameter and on higher lift cams, even that requires notching the top of the cylinders.

Sorry, I was confused. I thought you were doing 5.3 engines. Duh. See, READ the posts completely. That goes for me too.

[novadude]

Wonder if you can find someone that can machine down a quality 1.94 valve to 1.85-1.87? Mark Jones sold me a set of BBC valves that were cut down to a 2.11 size from 2.19 for a small bore BBC.

[Frankshaft]

Wonder if you can find someone that can machine down a quality 1.94 valve to 1.85-1.87? Mark Jones sold me a set of BBC valves that were cut down to a 2.11 size from 2.19 for a small bore BBC.

Just an fyi, a ferrea 5000 or 6000 series 2.11 11/32 stem valve for an Edelbrock Pontiac head, works perfectly for that application. If your doing guides anyhow, might as well do 11/32 for the BBC. They are 5.25 long. About the same length as a stock BBC valve. Sorry to hijack the thread

[PackardV8]

Wonder if you can find someone that can machine down a quality 1.94 valve to 1.85-1.87?

FWIW, we bought eight sets of 6.0 2.0" intakes and a friend with a CNC lathe cut them to 1.875" just zip/pop, so smooth they didn't have to be touched up on the grinder.

It's just time and money, but if the correct diameter valves exist, why not buy them?

[Keith Morganstein]

Wonder if you can find someone that can machine down a quality 1.94 valve to 1.85-1.87?

FWIW, we bought eight sets of 6.0 2.0" intakes and a friend with a CNC lathe cut them to 1.875" just zip/pop, so smooth they didn't have to be touched up on the grinder.

It's just time and money, but if the correct diameter valves exist, why not buy them?

The valves are availible. SI , Manley, and others. Brian B at Dakota parts will get you Ferrea ( might be a custom, but not unreasonable in cost)

I’d use trend pushrods if the ends are correct, Smith Bros for custom. The biggest you can fit, but at least 3/8”

Valve springs, beehive or dual will work. A stock beehive spring such as an LS6 could work well, if you need more spring, go with PAC, but get the spring with more processing, suffix X or better. Otherwise a quality dual spring. It all depends on what will fit of course.