ianmcgee67179

I just had my 79 L48 rebuilt, bored to 383, put a slightly beefier cam(magnum cam), with some blueprint aluminum heads, for a little more power, and already have hooker headers and side pipes, and a 600cfm Edelbrock performer carb as well. I know it was a numbers matching car, that's why I opted to rebuild the engine instead of get rid of it.

The thing is I'm still hungry for more power. I can squeal the tires, which is fun, but Id like a bit more which brings me to wanting to get a new intake. After some research I want an edelbrock performer. I have read so much about that with a performer intake not being able to fit under a stock hood and how it can with a dropped base. I haven't been able to find the stock height for an L48 intake thought and I think this would solve the mystery for me if I have some hard numbers.

Or just some people that have done this same thing before?... Id love some help thanks for everything.

Dynra Rockets

What RPM are you looking to improve the power. 2800 or 5000+?

dmruschell

I was able to fit a Performer RPM intake under the stock hood of my 79 using the stock air cleaner and Edelbrock carb. I'm currently using a GM ZZ4 intake that gives even more hood clearance.

A Performer should fit just fine.

ianmcgee67179

I'm not sure if I understand your question honestly. But I would love some more at either or both, but if I could only have more power at one of those ranges I would want it at 2800.

ianmcgee67179

If you don't mind me asking why did you change to a GM ZZ4 intake rather then an edelbrock?

terrys6t8roadster

When I was looking at the Edelbrock website they were pretty good at stating "WILL NOT FIT CORVETTE" on certain manifolds. T

dmruschell

From what I've read on various forums from people with experience with the RPM, ZZ4, and Performer, the consensus seemed to be that the ZZ4's power range is extended a bit higher than the Performer, though not as much as the RPM. If Edelbrock rates the Performer to 5500rpm and the RPM to 6500rpm, the ZZ4 is a nice middle ground. My cam is rated to 6200rpm, but rarely sees over 5500rpm.

I've also read that the current Perforners are designed to produce low end torque. It's also been said that Edelbrock makes the ZZ4 intake. But, who knows.

I'm sure the difference is minimal, though. There is a dual plane intake shootout that was done by a car magazine a few years ago that compared 20 or so intakes. There are differences between the 3 manifolds, but it wasn't a huge difference.

The ZZ4 can also be had cheap on eBay, much less than I've seen the EGR Performers listed for.

Im going to be putting a Performer EGR on a 75 I'm restoring (engine is being built for max power under 5500rpm), and started a thread with pictures of both intakes for comparison.

SteveG75

Get the Performer RPM. It will flow better and fit under the stock hood with a dropbase aircleaner. Here is my info on the RPM Q-Jet under a stock hood. BTW, the Q-Jet is a much better carb than the Edelbrock "Performer" (renamed Carter AFB).

dmruschell

The OP said they'd rather have more power at 2800rpm than 5000rpm. The RPM may flow better, but flow doesn't always mean better low end torque (it often means less low end torque in favor of top end horsepower).

It sounds like a standard Performer (or Performer EGR) will be the best fit, though the Performer EPS manifold probably deserves a look if a Quadrajet is not to be used.

BKbroiler

You said your engine was bored to 383. Converting a 350 to a 383 requires boring and stroking - changing the crankshaft.

Is your car manual or auto? If auto, torque converter and rear gears make a huge difference in low end throttle response, i.e. burning rubber.

SteveG75

The rpm ranges that Edlebrock quotes are based on a 350. The 383 can use the Performer RPM airflow easily. I have had both and nothing was lost going to the RPM over the lower Performer.

ianmcgee67179

Sadly its an auto with a 3.06 back end, but here in the near future I will be putting a T56 Magnum in it. I know that'll change the Torque and power to the wheels but didn't think it would matter much with the intake.

I bored it but didn't stroke it, has the original crankshaft. She was just bored to a .030 to make it 383.

So your saying the original Quadra-jet Carb is better then a performer carb?...or is a Q-jet carb something different then the stock one?

dmruschell

A 350 with the original crank bored .030 over is a 355, not a 383. A 383 requires a different crankshaft, either out of a 400 SBC or one designed as a 383 crank.

I've put over 40,000 miles on Edelbrock carbs on my 79. They'll work just fine (though I am going to try out a Qjet on my 79 to see if I like it better... past experience with a Buick 455 was that the Edelbrock made more power than the Qjet, but that could have been a fluke). Most C3 Corvettes came stock with Quadrajet carbs.

ianmcgee67179

Yeah!... that's what I meant! 355! sorry I'm a bit new to this more serious stuff. I only bored it out and put new heads and cam on it.

I still have the stock rebuilt Qjet, I got the Edelbrock a while back thinking it would bring some more power...not doing my research I didn't even know still don't know the specs on the Qjet, (CFM ect)

Depending on which carb I use I think will help determine the intake as well, because the 1" conversion plate I have is killing me for space under my hood!!

ianmcgee67179

While were on the subject... is that the only real way I can get more real power out of my SB 350? Actually make it a 383 with a new crank and everything else it takes? Of course without supercharging any forced induction. ?...

dmruschell

All Chevrolet Quadrajets are 750cfm.

Every Edelbrock intake that is made to accept a Quadrajet will also accept an Edelbrock carb. The ZZ4 intake will accept both, as well. So, a Performer (with or without EGR), ZZ4 or Performer RPM Qjet will all allow you to use the Qjet or Edelbrock carb without any adapter plates.

I personally would go for the ZZ4 or Performer (EGR) manifolds for hood clearance reasons, and being able to use a heat insulator gasket if needed.

dmruschell

If you've already put in a cam and heads that work well together, the only thing left is the intake.

If you can spin the tires, more power is only going to spin them more.

Chsnging your rear gears from 3.08 to 3.55 or similar will help a bit. According to the 79 user manual, automatic L48 cars were supposed to have come from the factory with 3.55 gears. Though, that will mean higher rpms on the highway.

mrichi

Put a big block 454 in it you can't beat more cubic inches

SteveG75

If it a 355, the regular Performer will work fine.

The Q-Jet is an excellent carburetor. It is actually a mechanically secondary carb that has a spring loaded air flap that opens on demand so a well tuned Q-Jet will never be "too much carb" for the engine. Remember, GM used the Carter AFB (which the Edlebrock is based on) back in the '60's. They dumped it for the Q-Jet to get both better performance and better mileage.

SteveG75

For the same $$$, get the stroker crank. 454 .060" over and 1/4" stroker is 496 cubic inches. Love mine.