Any Ford folks on the forum?

I was wondering if there was a noticeable (street driving/highway, NOT racing situations) between the 2121 and 7121 Edelbrock Performer intake manifolds?

This is pretty much the only manifold that will fit under the hood of the MGA with the Edelbrock 600 carb and Accel distributor. I know that one offers an EGR option and one has a slight RPM advantage over the other, but for regular around-town driving, are there really any differences that I need to be aware of?

Motor is a simple '89 5.0 with headers, otherwise stock.

If anyone has a preference or experience or like/dislike for/with either one, I would sure like to hear from you. Totally new to small block Fords and need some real world info.

Any help at all would be huge ! !

Thanks,

TC

I can't speak directly for those two manifolds, but for a street car, I'll take having an EGR over not having one. When it's working properly, an EGR is only "on" under light loads, where it gives you a slight bump in fuel economy. Elsewise it's closed and may as well not be there (other than a little more complexity/ugliness under the hood).

And on the flip side, Edelbrock's Performer RPM manifolds with no EGR provision actually block off the passages at the head, so the entire intake and carburetor stay cooler. In a small, cramped engine bay that can be useful, especially if you're boiling gas in the float bowls.

That said, I had the "regular" Performer on my 289 Mustang, and it worked very nicely.Bigger engine bay than an MGA too, though.

Thanks guys, good tips, still wondering about the driving characteristics between the two, although Javelin's mention of how the basic Performer work on the 289 is encouraging.

I want to run the Performer over the cast iron 289 stock four barrel manifold in an effort to keep the heat down. I thought that the aluminum manifold and aluminum Edelbrock carb along with a thin Phenolic spacer might do the job. Possibly fashion an aluminum tray as well to isolate the hot air beneath.

I'm installing twin circular vents on either side of the grill to bring cold air to the intake and carb body itself. Another precaution. There might also be a need for a power bulge in the hood, should the heat become too much, I could open that up into a small scoop.

Sort of thinking ahead for what might come up later on.

Thanks,

T

If you're that worried about heat, I'd go with the RPM. I assume this isn't a DD?

I'd do without the EGR every time. I've never missed it on any of my cars even on 20F days. Admittedly my cars have not generally been daily drivers (well the Barracuda was for a year with the EGR flapper on the exhaust wired open, disabling the system), but I've never had a carb ice up or suffered unacceptable (to me ) fuel economy.

Dave

Get an RPM Air Gap if at all possible, the main reason to buy a stock Performer (2121) or even a Performer RPM (7121) is for appearance, weight, and the sweet sweet marketing.

Aluminum transfers heat like a mofo, thats why the Air Gap is so awesome.

RPM (7121) and RPM Air Gap (7521) are 3/4" taller than a standard Performer.

One other factoid, the rpm air gap w/ drop air filter is LOWER than the factory EFI.

Or maybe it doesn't matter. If you live in cold country . . . well, I wouldn't do it again (he says after buying two air gaps . . . .???)

have fun

In reply to TeamEvil:

I've used both on a SBF, along with the air gap. I'm not sure you'll notice a difference in any of them in your app. The Performer has a lower RPM range, the RPM and the air gap are higher, and the air gap theoretically insulates heat better. I'm currently building a stroker for my Mustang and am using a modified Air Gap manifold, although I may switch to a Victor Jr. at some point. But if your 5.0 is really stock, then the regular Performer is likely going to work the best for you. The stock cam and heads on the 5.0 don't allow it to breath well in the higher RPM ranges (above ~4500 RPM) where the performer and Air Gap shine. So my recommendation would be to use a regular Performer and block off the heat crossover, which can be done with a sheet metal plate that you can make or is included in many gasket sets. It' s just better matched to the performance characteristics of the stock engine. And wrapping your headers will do more for reducing heat than any intake manifold vs another.

As always, great info!

As this engine is going into the MGA, height is a severe problem, even counted in quarter inches. The 5.0 came from a nicely running parts car with the T-5 and Traction-lock rear end, I'm hoping that the gearing will compensate for the low top end RPM. Since the MGA will essentially get a complete Mustang 5.0 GT drive-line transplant, it ought to react as the Mustang did. Pretty OK.

The only non-stock items in/on the engine are a F303 cam and BBK shorty headers, I'd planned on wrapping the headers for the first five inches to protect the plugs and wires anyway, but have enough wrap to do more if needed to control the heat. Given all of this, I guess that the EGR equipped Performer 289 or 302 would be the best bet for now.

Thanks for the very specific information, still have a lot to learn about these engines. I've heard that there are some neat heads out there that will bolt right on and can be had off of a van/SUV that's a pretty common scrap yard occupant. I picked two other 5.0 engines to play around with. Probably install this current one with a few modifications and build up another better engine for afterwards.

Again, thanks !

TC

You can use Explorer heads off the later V8 explorers, they are a bastardized GT40 head but they are nothing spectacular any more by the time you buy them and have them machined you are still stuck with some weird iron factory heads for half the cost of a decent set of real heads. They were a good deal in 1999 when you could get them out of a wrecking yard and decent aluminum heads were more expensive and tougher to find used.

Case in point, average machine shop work around here for a head refresh is around $300 depending on what you need. My friend just sold a used set of Performer RPM heads with Comp rockers for $800. Thats a no-brainer for me, just buy the decent aftermarket stuff.

What the berkeley is a carburetor???

I used to be a ford folk until the engine in my contour blew up

TeamEvil wrote: I was wondering if there was a noticeable (street driving/highway, NOT racing situations) between the 2121 and 7121 Edelbrock Performer intake manifolds? ...for regular around-town driving

"Street", "highway", "regular around-town" the #2121 Performer will be snappier than the #7121 Performer RPM.

As an aside I recommend that you fully research your carb choice. Most people in my world who have tried it have come to the conclusion that the SBF, Edelbrock carb and our light weight cars don't play especially well together and wind up happier with something like a Holley Street Avenger 570 or 670 (in your case I think a 570 would be just right).

RE: heads, the 302 engine used in Explorers up to mid 1999 were cast iron GT40s which are better that the E7 heads from a Mustang 5.0. Better still are the mid 1999 up GT40P heads however the spark plugs were relocated which can pose complications with header fit in some cases.

Jeff

If you're considering buying factory heads and having them re-done, I have a set of modified 351W heads that will outperform any Ford factory head, and I'd let them go cheap. But fair warning, I'm not using them because they, like any other factory head, aren't worth putting a lot of money into. It doesn't take much machine work until aftermarket aluminum heads start to look appealing. And in an MG, I'd bet you could use to lose the weight.

"wind up happier with something like a Holley Street Avenger 570."

Thanks, for that tip ! ! ! Nobody has mention it to me at all, the Edelbrock was totally the carb of choice.

Thanks all for the good information on those cylinder heads ! We don't usually end up with a whole lot of good used after-market parts around here, but I have time to shop around and check eBay and all, not doing a whole lot to the other engines until this first one is done and in the car and running.

T