Club Cobra - Performer RPM Valves

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Performer RPM Valves

The Performer RPM FE heads use the 428CJ valve sizes, 2.09 and 1.66. Supposedly they can be machined for 427 valves, 2.19 and 1.73.

Anyone done this? Any flow data on the difference?

I think Edel offers a FE head that already has the larger 427 valves in them. I don't trust my memory, but I think I remember reading this.

Think the 427 valve sizes are based on larger guide center distance & Edelbrock market a head so machined seperately with the 4.25" plus bore in mind.

I'm using the Ebock heads w/larger valves in my 428 and they clear the cylinders no problem. No flow data though. Try the FE forum for that info Guns, you know one of those guys has it.

Steve

Quote:

Originally Posted by Jac Mac (Post 1024675)

Think the 427 valve sizes are based on larger guide center distance & Edelbrock market a head so machined seperately with the 4.25" plus bore in mind.

From the JEGS catalog:

Quote:

Complete heads include stainless steel 2.09'' intake and 1.66'' exhaust valves to clear the 4.050'' bores on a 390ci engines. These 428 Cobra Jet-sized valves promote excellent flow for streetable power, and the large valve seat inserts can be machined to accept 427 Ford Medium Riser valves (2.19''/1.73'') if desired.

Maybe it's just garbled catalog info, but that sounds like these heads can be re-machined for the larger valves.

Just one thing I'm considering in an engine warm-over. (Roller cam, some head work, maybe these larger valves.) The project will all be in Tom Lucas's hands over at FE Specialties, when I get over to talk with him.

Not that uncommon. I believe all the major FE builders do it for the larger cube FE's.

I think the Eboks can even be machined (seats cut) for the 2.25s. I believe KC's stage III FE Eboks have the 2 .25" intake valves. Non-CNC'd, I think the flow capacity between the 2.09s and the 2.19s would be minimal. I believe it's the CNC process PLUS the 2.19" intakes that really increases the flow, around 320-340 CFM @ 0.650" intake valve lift.

Dave

Gunner save your money

Gunner Call Keith Craft, Tom L. or Barry R and get a set of heads with the 2.19" better valves and a CNC port job. Stage 2 or 3. 2.09 heads are replacement heads for stock motors. Yes some guys race them with alot of custom parts. Do it once and forgetaboutit.:cool: This will save you money in the long run. Ferra valves are better than the Edelbrock ones too. You can also have 11/32" valves installed instead of 3/8" ones and get a little more flow out of the head, lighten the valve train a little and get a couple more 100 rpm before float problems start. Compare a set of heads that are bare blanks with the needed parts to complete one with all the machine work done. The other thing is to send out the intake manifold to Joe Craine to have it ported and flowed balanced for motor. There are some manifold that have between a 10-30 cfm differents in flow on each port. This takes about a week and is the BEST money you can spend.:D He gets the ports to flow between 3-5 cfm from high to low. This helps to balance out the motor and have no leak cylinders from a/f mixture. Rick L. Ps you want the valve springs to match the camshaft in the motor%/

It depends on what bore size it's going on. With a larger intake valve, it may be shrouded and not help at all on a smaller bore.

We often put a 2.200 11/32 intake and a 1.71 11/32 exhaust into Edelbrock heads. The intake clears everything on a 4.080 bore with no problems. The exhaust gets tight on 390s - you're best keeping that smaller - we do 1.660 on those.

Between the bigger valve, smaller stem, Newen CNC valve job, and some modest blending we see about a 30 cfm average gain in the working ranges from .400 to .600 lift. This is without significantly modifiying the port opening at all.