[Stuckinda60s]

I bought a Performer RPM, several years ago, and just went to install it after having it matched to the gasket and the ported 7K3 heads. Imagine my surprise when it didn't fit! The heads had a cleanup cut of .020. I usually do .025, but I didn't specify and the shop did .020. I've never had a problem doing this with any manifold in the past. On this one, if I can get the bolts in one side, there's no way the others will fit. Also, the runners won't allow you to use a socket to install the bolts, they're too close.

I've installed several Torquers, a Dominator, a couple of Performers, as well as countless factory manifolds without issue with an .025 cut without touching the manifold side of the head or the manifold.

I'm trying to get this car ready for Norwalk and don't need this kind of aggravation. particularly since I had pasted the gasket down with RTV and was going to clamp it in place to set the gasket and then do a final check of the port alignment.

Anyone else had problems with Edelbrock fit?

[Big Injun]

That is a routine issue with the Performer RPM. Back to the machine shop you go...

[Stuckinda60s]

Thanks, Dave. I could understand if the RPM was new and this was a teething issue, but it's been out for a long time and things should have been rectified.

It makes me wonder if there is a similar alignment problem with their heads and the heads and manifold will work together but not individually?

[Stuckinda60s]

Now I'm wondering which way this problem should be addressed. Should the holes be elongated or should the head-mating surfaces have a cut taken on them? If the head surfaces need to have a cut taken, does anyone know how much it should be? How much has anyone taken off when they've addressed the problem? I'm thinking maybe .050 a side?

[6T5 Cat]

I've bought 4 Performer RPM manifolds for 4 different Pontiac engines I built over the last 10 years and I had to have each one of the manifolds cut .060 in order for them to fit properly.

[HWYSTR455]

We feel your pain, and are here for you! It's something you would THINK they would have corrected, but on other posts, it looks like they don't acknowledge there actually IS a problem. When I called the one time, few years back, I told them to just look on ebay at all the ones with cracked exhaust crossovers, that should be clue enough!

It's not limited to Pontiac intakes either, just did a swap from a Performer to an RPM on the Olds, BOTH had the same issue, had to have them cut. The RPM I didn't even try, I sent it right to the machine shop. Even they said "Wow." .

.

[HWYSTR455]

Just did a google search with the string "Performer RPM cracked exhaust corssover" and got hits on Ford, Mopar, and Olds foums on it, so they have to know there's a problem...

FYI - I cut the Olds ones .050 and use thick gaskets ....

.

[Tim Corcoran]

First off I would not elongate the bolt mounting holes unless your port alignment is right on but I bet it is not. Also you don't need to use RTV or any sealant on the intake manifold except maybe a tad around the water crossovers and where the rubber seal meets the thermostat housing. I had that problem with a Victor a while back and turned out to be exactly .040 too high the same thickness as the Felpro RA IV intake gasket. So I left the gasket off and put a small amount of RTV on the manifold around the ports and have been running it like that for years with no leaks or any other problems. The ports line up perfectly too. Good luck

[Stuckinda60s]

I smeared a minimum amount of RTV, probably wouldn't even be measurable if I had been able to clamp the manifold down. I used it as an adhesive with the orange plastic guides to hold the gasket in place because the ports have been gasket matched.

Maybe, as in your case, Tim, the ports will line up without the gasket, but it didn't look like that would be true, yesterday. Realistically, I knew I'd have to have the manifold cut, I just didn't want to face it and the delay it would cause. I was more asking how much would be necessary.

I'm led to wonder if they didn't allow for a gasket when they machined the gasket surface. Maybe they expected everyone to use RTV? Or, maybe they just overlooked the need for clearance for gaskets. I haven't checked port alignment, but I'm sure it's off. The gasket lines up perfectly with the head using the guides and likewise with the manifold. There's probably at least .100 mismatch per side.

The openings for the water passage are less than half the size of the gasket, even though there's enough meat to make them the same size. Coincidentally, the holes would open up if there was a cut made.

My 35-yeqr-old Torker is a work of art compared to this piece. I guess I'll use that, although it will cause me a tenth or two. Oh, wait, I forgot the Torker is matched to RAIV heads, sigh... I guess I'll use a modified factory manifold. That's great, I did the port work and chose the cam around the RPM. It's always something.

[HWYSTR455]

Wow. .100? Double-wow. Maybe buy another and see if you get lucky? Send the other back?

.

[Grand73Am]

Wonder how many have been able to install the RPM as it is without problems?

[HWYSTR455]

Originally Posted by Grand73Am

Wonder how many have been able to install the RPM as it is without problems?

Scenario: People try. Then they have vacuum leaks, tighten the crap out of them, they heat cycle, and the exhaust crossover cracks. If you're lucky, you can goo the heck out of the thick gaskets and not have a leak, but the ports won't line up.

It's a gamble, some intakes come out ok, or even pretty good in some cases, which maybe it's worth trying again with a new one. Pick a supplier who sells a ton of them, so it's not one that's been on the shelf forever.

.

[Stuckinda60s]

Thanks for the advice. I've had mine for several years, I Bought it, unused, from a forum member. I couldn't trade it, anyway, because it's been ground on. And I don't particularly feel like going through this with another one as a pig in a poke.

Don't forget my heads have had a .020 cut. If I start a couple of bolts in one side, I can't start them in the other. It would probably take .040 before I could and that wouldn't center the manifold over the bolt holes. It's a shot in the dark as far as how much to cut, but I need enough to give some movement to align the ports. If I can center the manifold over the bolt holes, I should be good as far as the ports go. At least I'll be a lot closer.

There's still the issue of the runners not giving enough clearance for a socket to tighten the bolts. I'll have to clog up a few carbide burrs to fix that problem.

[Tim Corcoran]

I bought an RPM in 1994 and it fit perfect right out of the box. Still have it too.

[Overkillphil]

I always budget an extra 100-125 bucks when I buy an Edelbrock intake. The machine shop that cuts them for me sees them all the time like this. Funny, when I phoned up an Edelbrock tech he acted like he never heard of this. Yeah right.

Interestingly, last month a new RPM intake for my SBC boat engine project fit perfectly right out of the box on the E-tec heads.

[Stuckinda60s]

I also had to grind the bottom of the flange to clearance the valley pan.

[Matt Meaney]

I had the same problem. the intake fit very nice without any gaskets, so I had the intake cut the same thickness as the gaskets were. If memory serves it was .060 on each side. the machinist commented that it took .010 just to get them straight. yes, this was a brand new, never used intake.

[Stuckinda60s]

Originally Posted by Matt Meaney

I had the same problem. the intake fit very nice without any gaskets, so I had the intake cut the same thickness as the gaskets were. If memory serves it was .060 on each side. the machinist commented that it took .010 just to get them straight. yes, this was a brand new, never used intake.

That was what I determined, this afternoon, that I needed a .060 cut. I ran to town to a machine shop and asked if he could squeeze it in. He's going to try to have it done Monday for me.

[HWYSTR455]

Well, that sounds promising, hope that works out for you.

Oddly, the last RPM I bought for the driver fit out of the box, with e-heads. The one I replaced was close, but after about 20k miles, it leaked, which is why I bought the new one. I just happened to try it before I took it to the machine shop. Guess I got lucky!

I bet the reason I had an issue with 2 Olds intakes in a row is because they sat on the shelf in the warehouse for a while, bet those move slower than ones for Pontiacs.

.

[Stuckinda60s]

Originally Posted by HWYSTR455

Well, that sounds promising, hope that works out for you.

Oddly, the last RPM I bought for the driver fit out of the box, with e-heads. The one I replaced was close, but after about 20k miles, it leaked, which is why I bought the new one. I just happened to try it before I took it to the machine shop. Guess I got lucky!

I bet the reason I had an issue with 2 Olds intakes in a row is because they sat on the shelf in the warehouse for a while, bet those move slower than ones for Pontiacs.

.

It's apparent from the way they fit without a gasket that they never added it into the calculations when they laid out the job. Plus, the way they fit the E-heads, it appears that the heads and manifolds will fit when they're used together. I'm betting that the E-Heads present a problem when they're used with another maker's manifold.