Edelbrock intake info needed.

Anyone know what the difference is between the Edelbrock Performer 2121 intake and the 7121 intake for the early 5.0 Ford engine?

They look the same on paper, but I'm wondering if there's a spec change that will make a difference when picking the carb or possibly in the effective rpm range?

Need some help with this one.

Thanks,

TC

The 7121 is a Performer RPM, not a Performer.

The main difference is manifold height - the RPM manifold sit the carb higher, which is beneficial for the center cylinders, at the expense of hood clearance.

Like Knurled said, the 7121 is the RPM intake. It's advertised 1500-6500 RPM. So depending on what cam you are running in that 302, it could be a good improvement over the regular Performer (idle-5500).

I've used the Performer, Performer RPM, and the Performer RPM Air Gap on different small block Mopars. The Performer is basically a good intake for a very mild/stock motor. Anything more, go with the RPM.

Be careful if you're buying a performer, sometimes the only improvement is the weight.

The Pontiac version of the Performer was just a (poor) copy of the cast-iron Pontiac Ram-Air 4-barrel and it flowed worse than the stock item.

Shawn

You guys all missed the really big difference between the regular Performer and the better Performer RPM.

The RPM's have no exhaust crossover! Way more power, cooler intake temps, cooler carb/fuel temps, harder to start.

Don't need a Performer RPM for that, a piece of shim stock will fix an exhaust crossover.

Thanks guys ! ! Great info. The 302 isn't anything special at all; an '88 engine, a little port work, f303 cam and dual valve springs. Otherwise, stock.

It's going into an MGA and clearance is an issue, but a big or a bigger bulge in the hood might not matter if the difference in performance is great enough.

Anyone know if such a mild engine would benefit best from the 7121 or would the 2121 be just a as good in this case?

Anyone know the difference in height between the two manifolds?

The car is only for the street and highway, not for playing around at the drags at all.

Thanks !

Trans_Maro wrote: Be careful if you're buying a performer, sometimes the only improvement is the weight. The Pontiac version of the Performer was just a (poor) copy of the cast-iron Pontiac Ram-Air 4-barrel and it flowed worse than the stock item. Shawn

Olds Performers are similar to this as well. Not a great improvement in performance but then you are dropping like 15 pounds or something from the stock intake weight. I have a Performer to go on my 403 but then I got it used for a good deal.

As the engine is going into an MGA, I could settle for just the weight savings alone, additional performance would be a plus for sure though.

With the big swap meet coming up at the former Great Woods, I'm trying to figure out what to look for as far as the intake goes. I was thinking of maybe some under drive pulleys as well, maybe a Holley 600 and a dual point or Unilite distributor.

Anyone had any luck with those HEI distributors on the small block Fords? I kinda like the tech, but they seem sort of large and may not clear the hood.

Just wondering?

Whatever you pick, make sure it's a dual-plane manifold. much better for street use.

Why not consider an Edelbrock (carter) carb or a Quadrajet.

The demand-based secondaries on those carbs do a very good job of making sure the carburetor is always the right size for the engine. Plus, there's no gaskes below the fuel level like the Holley Car-b-que carburetors.

Shawn

rebelgtp wrote:

Trans_Maro wrote: Be careful if you're buying a performer, sometimes the only improvement is the weight. The Pontiac version of the Performer was just a (poor) copy of the cast-iron Pontiac Ram-Air 4-barrel and it flowed worse than the stock item. Shawn

Olds Performers are similar to this as well. Not a great improvement in performance but then you are dropping like 15 pounds or something from the stock intake weight. I have a Performer to go on my 403 but then I got it used for a good deal.

Mopar ones too. The small block one is nice on a stock 318 when converting over from a 2bbl. Ports are a little small for a 340/360. The B-engine ones same deal for converting over from a 2bbl. Every other combo is just good for weight savings.

TeamEvil wrote: As the engine is going into an MGA, I could settle for just the weight savings alone, additional performance would be a plus for sure though. With the big swap meet coming up at the former Great Woods, I'm trying to figure out what to look for as far as the intake goes. I was thinking of maybe some under drive pulleys as well, maybe a Holley 600 and a dual point or Unilite distributor. Anyone had any luck with those HEI distributors on the small block Fords? I kinda like the tech, but they seem sort of large and may not clear the hood. Just wondering?

I think that f303 cam would like the RPM better. If you are willing to do some clearance work on the hood that would be the intake I'd run.

The Holley 600 in a vacuum secondary would work fine on there. I prefer the Edelbrock/Carter style carbs that TransMaro was mentioning. A 600 Performer or 650 Thunder Series would work well with that cam and intake. You'll probably find more Performers and Holley 600's at the swap meet. The Thunder Series is a little newer so not many of them floating around used yet.

I wouldn't run a dual point or a Unilite distributor these days. If you do score a good used one of either consider PerTronix module to replace the points. I think they also have a module to replace the electronics in a Unilite too. At least I think I saw that in their catalog. Pretty straight forward install and no need to worry about setting point gaps again.

They also make ready-to-run distributors. I have one on the shelf waiting for me to finish a 351W for a friend's Mustang. The cap diameter is much narrower than an HEI setup. But they are a bit on the new side as well so you might not come across any used ones just yet. Probably more Mallory/Accel/MSD used ones to choose from. Nothing wrong with any of them and rebuild parts should be available from the manufactures.

Trans_Maro wrote: Whatever you pick, make sure it's a dual-plane manifold. much better for street use. Why not consider an Edelbrock (carter) carb or a Quadrajet. The demand-based secondaries on those carbs do a very good job of making sure the carburetor is always the right size for the engine. Plus, there's no gaskes below the fuel level like the Holley Car-b-que carburetors. Shawn

every Performer intake- be it a regular Performer, Performer RPM, or Performer EPS- is going to be a dual plane. the Edelbrock single planes are sold as either Torkers or Victors..

regarding this particular engine and car- i'd just go with the 2121 and put a 600 Edelbrock carb on it and call it good. that will be enough intake and carb for up to about 350hp, which will be hard to get to with any stock head short of a set of either ported E7's or GT40's from an Explorer and some good long tube headers.

i like to keep the exhaust crossovers open to get the plenum nice and hot and ram as much cool air into the carb as i can for maximum fuel economy..

Once again, thanks guys ! Tons of help here in figuring things out.

The only reason for running the Holey 600 is that I have a nice one down cellar, otherwise I really do like the Carter/Edelbrock carb. If I can score one at Great Woods/Tweeter Center/whatever I'll use it instead for sure.

Was sort of thinking that the Performer would be an easy choice, especially considering that this engine would never make the horsepower for a Performer RPM to be necessary, but I DO kinda like the rpm boost that the Performer RPM offers. Good to hear from folks with knowledge about these things that, in the real world, either would probably work just fine. I tend to get caught up in the chase, read a lot of on-line articles and reviews and think that I just HAVE to have an engine that will turn 7,000 rpm or I'll just die.

I used the Pertronix module on the Porsche, and really like them a lot. Since I have a new spare Pertronix II "Flame Thrower" coil already, I'll have to keep a look out for a decent dual point that I can get a Pertronix set-up for and just run with that. Seems like a good solid low priced way to go. I really like the low profile of the stock distributor, but I've heard tales that they really do need to be replaced for a reliable non-computerized engine.

With the restrictive engine bay, I wouldn't be able to squeeze in a set of long-tube headers to take advantage of the bigger heads anyway. I have a set of the shorty BBK headers that I kinda plan on swapping around side to side and maybe running them out the front of the engine. I suspect that there will be some cutting, splicing, and re-working some of the tubes, but the MGA has a "goal post" set onto the frame and the forward diagonals will prohibit the headers from running rearwards. Not even room to run to the rear with a quick 90 degree turn-out.

I'd like to run them forward (like on the TVR) and down on either side of the crank pulley, back on either side of the oil pan, and outwards around the bell housing towards the rear.

I hope, anyway.

Anyway, as always, thanks for this information, I'd be pretty lost without all of your help ! !

TC

TC,

Is there room in the chassis to run some center dump headers? Something like these:

That company is making them for a 302/MGB combo.