RPM manifold

[CaptCobrajet]

I don't know of anyone who has bad things to say about the Ed RPM manifold.  At this point, I am going to have to label it as one of the FEW parts that seems to work on just about anything you put it on.  There are cases where something else would be better, but I have come to the idea that the RPM will always work, and better than most others, in a lot of cases.  I have used it on many street strokers up to 482 cubes, and up to now, 670 hp was the most I had seen using it, mainly due to camshaft and cylinder heads used with it.

I had a build with hood clearance constraints, 434 inch FE, for endurance/circle track use.  It needed a broad range, able to recover from 3500-ish rpm, but needed to hold it's head up past 7000. I used a healthy circle track solid roller cam.  I talked myself into using the RPM instead of one of the lower profile single planes.  I worked the runners about four inches in from the flange, and matched to the heads, and also spent some time in the plenums.  I cut the divider down about an inch, and blended the front and rear to mate with a 1-inch transition spacer.  The engine made a gob of torque for 434 inches(616 peak tq) and it made 731 HP at 6700 rpm with the dual plane!!  I've been rolling it around in my head for three days.  The rest of the engine was all "good stuff" but I keep coming back to the intake manifold and shaking my head.  I turned one over and have been studying the runner layout.  It is basically two single planes.  I think when the divider is worked and they can interact a little under the carb, an otherwise very good manifold becomes a real gem.  Hat's off to Edelbrock.  Whether they meant to or not, the RPM continues to prove itself a really good piece.  It also works on smaller, less modified builds with great success.  I have seen less benefit to the plenum and divider work on smaller cam, smaller cube combos, but still, the point being.....when your combo puts you on the fence about going to a single plane, the best move, in my opinion, is to go RPM and consider mods that fit the idea.

[wayne]

I  always liked all their stuff it always seamed just a little better back when the f4b came out for small blocks. It ran a lot better then the offy i had.

[Drew Pojedinec]

Funny thing.  The performer rpm seems to be excellent on FE builds as you mentioned (I run one on a super mild 390 and it's great there too).
The Performer for the FE is kinda meh.
The Performer for 460's seems soooo much better while the 460 RPM is ok.... not a bad intake at all, but certainly not the equivalent of the FE version.  I too wonder if it was dumb luck or some stroke of genius.

[CaptCobrajet]

I'm with you there Drew.  My big 385-based 540 (tow rig) likes the regular Performer 460 much better, even that many inches.  The air gap RPM 460 is huge......too big for mildly cammed 385 series stuff.  I dynoed a 390 yesterday with an RPM and a 232/238 hyd roller.  I'm going to post it in the dyno section, but it had nice flat torque, even in a 400 incher with a relatively small camshaft.  Definitely different animals.  I would not recommend the RPM 460 unless it was a big engine with a lot of camshaft.

[KMcCullah]

Damn that's some frisky torque, BP. What kind of compression with this bad piece?

When I did the RPM intake for my hot rod 390, I just port matched the ports that flowed the worst and left the better flowing ports alone. I found a thread some place where Joe Craine posted the stock flow of each port. So I kinda had an idea how much to port match the slow ones. It seemed kinda red-necky....... but it won a few races. 

[jayb]

731 HP from 434 cubic inches is a monster in my book.  Congrats on a great motor.  What carb did you use on that?  And I wholeheartedly agree on the Performer RPM, it performed very well on every engine in my dyno tests done for my book.

[BigBlockFE]

Their not the best looking intake but they sure work.

[CaptCobrajet]

Jay and Kevin.....that engine was 12.5:1 static.  BP hand ported BBMs.....spent about 10hrs on the pair.  The cam is a tight lash oval track solid roller, 270/278 on a 112, and .720 at the valve.  The carb is a 1.590 venturi, 1.750 bore Holley that I sent to a really sharp carb guy.  I gave the man some pertinent info on the engine, and he nailed the tune.  I generally have to work on the high speeds and emulsion on the dyno, but on this one, I did not even have to change a single jet!  Bolted it on and boom....12.8 A/F and no changes.  Couldn't believe it.

[Barry_R]

I wholly agree on the RPM intake.  Almost a "can't lose" piece.  I've had a bunch of them (like one every other week) and they always make way more torque than a Victor and rarely give up anything significant at 6500 or less.

They seem to be pretty reactive to carb spacers, but it's a "try it and find out" sort of deal, where one combination will want open, while another wants a 4 hole.  So far my best guesses revolve around seeing a side to side variance in A/F on the dyno.  If you see a big difference - like a full "ratio" - the open seems to even things out and you can get more aggressive & find some HP.  If they are fairly even the gains are small.  I've seen a 4 hole add a ton of torque down below peak, but not always.  Probably changes in the car.

[CaptCobrajet]

We dynoed two engines this week with identical heads and manifold.  That 434 solid roller wanted the 1" transition spacer.  The 390 with a much more docile hydraulic roller did best with only a 1/4" insulator gasket.  The open spacer hurt it, and the transition spacer hurt it down low, did nothing in the mid-range, and only made 1-3 hp up top.  I think the spacer thing is combo and cubic-inch specific, no doubt about it.  We pulled that 434 incher well past peak, and it really never fell off a cliff, just gradually lost power.  The intake was not giving up, even past 7000.....really surprised me.

[wsu0702]

I wish that the Performer RPM intake was designed to work with the factory shaker hood but it puts the carb about 3/4" too far back. 

[turbohunter]

Hey guys would the RPM work as well with port/runner injection EFI?
I have not seen an Ed supplied port equipped version as in the Victors. Could make one I'm sure but.....?

[jayb]

I wish that the Performer RPM intake was designed to work with the factory shaker hood but it puts the carb about 3/4" too far back.

Actually there are some slots in the shaker assembly that will let it move the scoop back and forth a little, and might allow the Performer RPM to work.  I've read that some people have done it successfully...

[Barry_R]

Hey guys would the RPM work as well with port/runner injection EFI?
I have not seen an Ed supplied port equipped version as in the Victors. Could make one I'm sure but.....?

Have not done an RPM.

I did a BT dual plane and it works very, very well.

Put 16 bungs into a BT 2x4, but that was for a 600HP CNG project that has only run on carbs so far.

[Rory428]

Hey Jay, In your GFEIC book, on the 410 & 425 HP 428 CJs, did you ever figure out why the Performer RPM was so far down on lower RPM torque? I am going to be putting in a almost bone stock 428 CJ in my 59 Ford 2 door sedan. It was a low mile engine that I had laying around in the garage for 25 plus years. It is still standard bore, with the original "428 Super" cast pistons, stock iron CJ heads etc, the only changes are a small Oregon Cam solid flat tappet cam, similar to a Comp 270S, a set of FPA shorty headers designed specifically for 57-59 Ford cars with a FE engine, and an aluminum intake. I am kinda torn between the Streetmaster and Performer RPM. I have both on hand, both untouched. In your book, both seemed to work quite well unported on a mild engine, but since the 59 will be fairly heavy, the RPMs lack of low end concerns me.I will be using either a 3310-1 Holley 780, a factory 780 from a 70 Torino 429SCJ, or a 4779 750 DP. Again, I have all these carbs on hand, so I am trying to make use of parts taking up space in the garage.