yankees

Well my Edelbrock RPM intake install (SBO 350) was a botched up success this afternoon. I used the SCE fiber gasket with no problems, but the damn intake bolt holes on the RPM manifold were way off where I couldn't even start threading 6 of the 12 bolts due to intake bolt hole misalignment.

I'm sure just about everyone on here who has tried to install an RPM intake has run into these problems. My next step is to ream the intake bolt holes ever so slightly to have some wiggle room. I've never seen something so poorly made from Edelbrock. Has anyone else had these problems with this particular intake? If so, how did you remedy the solution?



Thanks

coppercutlass

I'm not sure but my heads where to subject of the home porting thread. The op had me check for port alignment. The ports lined up but the holes where off. On my current 355 my heads where miled and so was the intake but the holes lined up. Just crappy castings I guess. In the case of those heads I belive 67cutlassfreak did indeed hit them up with a carbide just a bit so I would not fight to get the bolts in . In that particular intake it wasn't off by much but enough for me to have to drop the intake dead nuts center for me to get the bolts in.

don71

Manny, I haven't installed an RPM before.

The first thing that comes to mind is how much have your heads been milled? If its significant amount, you'll have problems lining up those bolts.

RetroRanger

I did an rpm on my sbo 350 last summer only had trouble w the two inners in the pass side, they both needed different bolts yo clear the intake runner other than that no problems...

don71

You'll have the same problem when installing a Torker as well. Its very important to dry fit everything...before using sealer. Just so you know what step (bolt)s to put in first.

yankees

The engine was all original before today. I'll ream the holes a little and try again this weekend. Wondering if the intake has been milled? The holes that were misaligned were from the back of the bolt holes, if standing in the front of the car. The ones that went in threaded easily, while others just wouldn't get started.

RetroRanger

are the threads clean Manny? I chased all my bolt holes before install. are you saying some line up and others dont ?

yankees

U can actually see the intake covering the holes just slightly in areas. Nothing a drill bit can't fix.

jag1886

If you are using the rubber end seals it will make the manifold sit high. I used a stock 4 piece set of gaskets for a 330 without the end seals and it went right on, it was tight but required no drilling out of the holes.

Fun71

I had no issues bolting the RPM onto my engine. Well, other than those two center bolts that RetroRanger mentioned.

olds 307 and 403

My RPM bolted onto my 403 with SCE intake and .040" Corteco head gaskets. I tried bolting on my Performer with Ultraseals on my stock 76 350, same results. Mine was so far off, reaming the bolt holes wasn't enough. I bought the Turkey tray instead.

yankees

Thanks everyone. I will get the fel pro metal gaskets without the tray and a set of mr gasket today. For the metal gaskets do u still use rtv around the water ports?

jpc647

I would. It'd also use rtv/"The Right Stuff" for the end seals. I took a performer RPM intake off my car last summer, and it seemed fine, the bolt holes lined up perfectly. As did the performer I replaced it with. Still have it in the garage, would be interesting to see if your rpm bolt holes are different than mine...

Octania

Sounds like fore-aft alignment issue?

I have only seen L/R bolt to hole alignment issues with an intake.
On the OEM intakes at least, exactly one "hole" is a slit with a carefully controlled width. which positions the intake fore-aft on the engine. Of course that bolt should be started first. The others all have generous holes in the intake to allow for manufacturing tolerances in hole placement.

If the heads and/or block have been cut too much, the heads are moved downward, and the intake bolts tend to interfere at the bottom side or inboard side of the hole in the intake. If the intake was milled too much, it would sit too far down in, and the intake to head bolts would hit on the top or outboard side of the holes in the intake. Neither of those will generate fore-aft alignment issues with these bolts/ holes.

jpc647

just wondering what happened. Did you end up slotting the holes to make it fit?

cutlassefi

I've purchased and installed a half dozen Edelbrock intakes on various block combinations in the last few months.
You guys won't want to hear this but fitment was poor on virtually everyone one of them.
Also I just did an Edelbrock headed 455 with an RPM. Nothing was square. We squared the intake and found out the intake side of the head wasn't 90 to the head surface as well.
Their standards aren't what they used to be.

yankees

I will re-attempt the install this weekend. Ordered several sets of different intake gaskets this time around. Fel pro, sce and mr gasket. Trying fel pro first. Anyone ever install the cast iron crossover plugs in the intake with any success?

jag1886

No but I have blocked them with a small piece of stainless steel, I found that a cheap stainless steel drywall knife from Home Depot is perfect material to make them out of.

Sampson

I would be interested to know why you removed the performer RPM and replaced it with a performer? I am in the market for an intake and trying to figure out the best for my car

s i 442

Well as of right now 3 hours was wasted trying to put a RPM intake on my 350 using after market gaskets. In no way was the intake going to bolt down.
I took the old turkey tray and and rubber ends and put them on and bolted the intake down almost too easy. So now the weekend is shot all ready, so i have to order a turkey tray and maybe next week it will all go better.

yankees

When using the metal gaskets is everyone spraying them with copper or putting rtv around all of the ports on both sides?

RetroRanger

i took my RPM off cuz I had to change to a small 2" tall aircleaner to close the hood w the performer i ran a 4" aircleaner

I didnt really notice any performance difference between the two but it was on a stock 40 yo 72 350 so "performance" may be a bit of a misnomer

Manny I just sealed the water ports w RTV and threw out the rubber end seals and did the ends w RTV as well no issues

yankees

Got the intake installed. Used the metal fel pro gaskets w/out the tray. Had to drill out the gasket holes on the ends as they didn't line up slightly. Used the right stuff on both sides and on every opening. Also used red spray tack on the head side, but not really needed with the protruding tabs in the gasket. Took a little moving it around to get the bolts in, but they went in. As far as bolts on the rpm intake, I had to use an allen head bolt in the one tight spot.

I also installed the cast iron crossover plugs with JB weld.

Tomorrow I will install the carb and fluids. Hopefully no leaks.

What size of bolt can I use to block off the water pump heater outlet in the heater hose?

Sampson

Manny I used the same procedure when I installed the intake on my engine when I rebuilt it. I have often wondered about the effect of using the RTV or Right Stuff on performance. That stuff had to compress and squeeze out into the ports a little. It seems this would effect the air flow. Anybody have any thoughts on this?

RetroRanger

Manny

On the water pump heater hose I used a hose barb and cap from plumbing dept in a hardware store, I'll try to dig up a pic. On the manifold a pipe plug from the same hw store blocked off the Hester port, I believe that was 3/4"

yankees

Thanks everyone!!! The car is running great with no hesitation and no leaks. It also fired up within 10-12 seconds with a 28 year old Holley 3310 750. I just need to adjust the timing, check the vacuum readout, and switch the 750 secondary spring to a heavier spring.

Off to cleaning up the engine bay, putting a gear/posi in it along with a better torque converter.


The only issue I did have and it was a big one, was that the throttle cable hung partially openon me (stuck at 3k rpm). I'm using the factory snap in 2 barrel cable, which may be the problem. The cable came out of metal casing under full throttle and got hung up on the metal tube sleeve when letting off the throttle. I hope a stock 4 barrel cable will remedy this? Anyone have one for a 72 that they want to sell today that is in good shape???


Thanks

coppercutlass

Fwiw my throttle cable is from a 2bl never had issues.

yankees

copper I remembered you using a 2bbl cable and mine looked fine testing it, but there was one time where I saw it get caught before firing up the Cutlass. Maybe the cable is old and just needs to be replaced.

I'm using Holley 20-88 cable bracket with a Moroso throttle return spring kit.

Should be a simple fix.

jpc647

That's strange. Mine was bolted down with aftermarket gaskets. My performer bolted down with a turkey tray style gaskets, but I used "The Right Stuff" for the end seals.

I have a stock 1972 Cutlass 350ci motor(rebuild stock best I can tell). It came with a 1406 carb and the rpm intake. I couldn't make it run right. Tried everything.

I then bought a 1405 carb and tried that. Better, but not quite there, so I finally broke down and tried a 3711 intake instead of the high rise intake. The rpm is make for non stock applications. With just a 72 stock cutlass motor, it's pretty weak, the rpm was overkill.

After adding the performer it was better still, but it's not perfect. Some days the car runs like a raped ape, but those days are few and far between. A lot of stuff happened at the end of last summer so I lost interest, and haven't jumped back into it yet, but I'm starting to feel like either the engine is just tired, and just sometimes has a good minute or two, or that I'm just expecting a lot out of a stock motor. They weren't hot shots when it rolled off the factory flow in 72, it's sure as hell not going to be one today, without a major overhaul. :/