RA4 intake valve's in a 6x4 head
 

I have a set of titanium RA4 intake valve's and I want to install them in place of a stock intake valve on a 6x4 head. I was told they would work, have to be shimmed because they are longer than stock 6x4 intake valve's. So the question is can they be lathe cut and re-groved for the valve spring lock, or am I better off just shimming them..

Also any input on upgrades to springs both intake and exhaust. .looking to run a .540 lift roller cam

Going by memory, a standard valve/valve spring height should be around 1.586" tall.

So if your titanium valves are .200" long you would be at 1.786" height which is very close to the normal RA-IV 1.800 valve spring height. Should be a easy mod to get to the taller Valve Spring Height and close to the geometry that the stock RA-IV engine had in production.

Tom V.

Thanks Tom V

Standard 6X are roughly 4.98. RAIV 5.20s. Heck just get some new springs to take advantage of the increased IH- a lot more choices 1.700-1.800. What are you doing for exhausts?

I have standard D port 5.10s in my 6X heads on the 400 in the 81 TA and ended up about 1.740 IH.

If those valves besides having the RA4 lenght also have the big Tulip back side of the factory RA4 valves then you will be loosing Intake air flow over what the stock basic nail head valves used in the 6X and all other D port heads have as I have seen in my flow bench testing of both valves in a D port head.

If you need further proof, then just look at the fact that no aftermarket head runs such a Tulip back Intake valve!

If your not also going to run darn close to the same lenght Exh valves in the head then you will need two different lenght push rod, and maybe custom lenght ones at that.

If it where me I would spend another 200 bucks and get the right replacement valves for those heads and leave the titanium valves on the coffee table as conversation items!

Going to give the a try, just had the heads gasket matched for RA4 intake gasket, and cleaned up the bowls, this was not an amateur job but from a friend that owns a cnc machine and does this for all types of heads.. regarding exhaust valve going with the stock 6x4 valves but upgrade to stainless steel..

I figured I have all these parts laying around and no one wants to buy them so I might as well see what I can build.

Regular Production RA-IV Intake valves are 2 Piece Valves. Ask Jim Brady how we know that.
We were at a track in Wisconsin run by Broadway Bob and Jim B did a burn out, was idling up to the starting line, and the Intake Valve head came off. Engine stopped and we could not turn it over. No real damage to the engine except replacement of the valves with ONE PIECE Intake Valves. In your case you have Titanium Valves so it should not be an issue. What is the measured length of your valves?

Tom V.

Your headed for a failure if you try and run those valves in a cast iron guide, as they MUST be used in Bronze guides unless the stems are heavily Chrome plated!
!
Does your buddy with the CNC machine also own a flow bench?

God how I love stubborn guys who want to build there motor with a part(s) that will cut there motors power output just because they have the Part(s) in hand!

And by the way my reverse flow test of a Tulip valve shows much higher levels of reversion / back flow which will cut into how low in rpm the motor can come on the Cam.

This is issue with the any motor , but with motors like the 428 and even more so the 455 due to there Bore to stroke ratio.

OMG, is this facebook?

Two different length valves? Stock length on the exhaust with a .540" roller cam?

You say you're buying new exhaust valves - why on Earth wouldn't you buy the same length valves as your intakes and save yourself a lot of headaches? Going to be hard to find springs for that cam at the stock installed height - the longer valves will help there. Would need two different pushrod lengths with different length valves also.

As Steve says, if they're the tulip head valves you're actually costing yourself power.

So how much power is lost by using a RAIV tulip valve?

I can't say with 100% accuracy due to not having control over the valve job that may or may not be done, also any porting work that could have been in conjunction with using those valves and the also the amount of lift that will be used, and most importantly the lift rate that the Cam lobes have and of course the rocker ratio used which effects the rate of opening.

With D-port heads in stock form and less then .450" lift applied to the valve I would place the power reduction at 3 to 4 percent which would also produce a power band that starts to kick in at a 3 to 4 percent higher rpm.

What makes original tuliped valves work in the RAIV heads and not in a D-port head using the same camshaft?

A flat valve works better in a RAIV head also. maybe up to 5% flow.

Please note that I am talking flow looses or flow gain across a give lift range, not just for example 8 less or 8 more cfm at let's say .250" lift , but like 10 to 12 cfm less when averaged out up to .500" lift.

Put that tuliped valve in a 455 HO or a D port head and you will see similar flow losses.

Hi Skip and thanks. Something we have known for a long time. Usually the tuliped valve will equal or slightly better a flat back valve above .600 lift on a good flowing head. Will and Steve25 seem confident about their being a power loss, I'm not sure there is. I was looking for more information. A tuliped exhaust valve usually flows a bunch better than a flat valve and we tried a back to back on a medium compression 455 and found nothing.

I'm not sure if it does "work" in a RAIV head.. It may work better in a RAIV head due to the higher short turn compared to a 455HO head or d-port. The deeper the bowl the more they tend to help. Hemi's seem to work good with a tulip valve, their intake ports come close to flowing straight at the back of the valve. A shallow port wants to flow across the valve and the tulip blocks it's path.

That seems like a lot of speculation.Might work good in the class room, but I'd need to see dyno numbers to believe it.

Do you think a tulip valve would work better on a wet flow bench at higher lifts?

I've run RA4 length valves in iron heads for years for the better valve spring installed height.
The op also said they were Titanium and I have never seen a Titanium valve with a tulip face
Just my 2cents

,540 lift w. 6x stock valve installed height is no bueno. The spring coils will stack up solid.

Use the RAIV valves you have and pickup a set of 1.77 RAIV Exhaust valves (Ferrea is fine). Have your shop machine the seats for them. I'm sure someone is going to say you need to rework the throats but that is BS. The throats behind the seat are way larger than the 1.77" exhaust valve and are not restrictive as is. Also, you don't need new hardened seats installed as the seat area is already induction hardened far enough outside the seat area.

You will gain additional exhaust flow, have the correct installed height to accommodate your cam's lift and can use the same length pushrod on intake and exhaust.