Edelbrock LD340 Intake Manifold Usable Max RPM?

[Fish Bite]

I recently took my car to a local chassis dyno and ran it with the LD340 intake. Combo is 4.06” bore, 3.58” stroke, 11.1-1 compression ratio, solid flat tappet cam (252/257 @ .050, .550 ish lift, 108 LSA). Intake was gasket matched and the plenum divider was cut down 1” and 2.5” length wise. This was topped off with a 750 double pumper. Here is the dyno graph for reference.

Edelbrock RPM’s that were touched up by Ray Barton.

I use the numbers as a reference. Was more interested in the power curve. I have tried the performer RPM, Weiand action plus, Victor 340 as well as the M1 single plane. I have been the happiest with the LD340 so far on my combo.

The heads have only had a valve job and the bowls cleaned up. I believe the camshaft is a little small, it was ground for a 3.31” stroke but I ended up finding a great deal on a 3.58” stroke crank and some .060” 360 pistons so it is now 371 CID.

I feel the car runs pretty good, pump gas, all steel, full interior and runs mid 11’s with a 4 speed at 118 MPH. I also feel the dyno numbers are pretty good for a motor that was designed in the 1960’s as there were several late model 392 challengers and 5.0 mustangs that were putting out low 400’s on the dyno which seems to line up with what others are reporting.

I have only had the LD340 on the dyno. I have run both the Victor 340 and M1 on the track with the M1 being a little over a tenth faster. On the street, the performer RPM was great off of idle but the LD340 pulls harder up top and the power doesn’t nose over like it did with the RPM.

This information is immensely helpful. Thanks.

What type and size headers are you running?

 

[TT5.9mag]

Right not my deal.

As an engine builder I despise rule makers who think they need to limit engines to junk **** to level the playing field.

Bewy thinks you can innovate your way around ignorant rules. It shows his lack of experience.


Parity means mediocrity. I detest both.

If I sound like an 18 year old it’s because the truth hurt your little feelings.

Class rules like that are bullshit. He can run decent compression. He can have headers.

But we will **** them on an intake manifold to make it “fair”.

If you can’t see the absurdity in that statement you are just too bone headed to see.

At least FAST classes limit everything. It’s still more expensive than it should be, but at least they have rules that make some sense.

It’s damn near always the corner turners who want **** to be “fair”. It’s stupid.

As for Stock Eliminator racing, no one should lie to themselves and THINK an intake manifold other than OE would be slower than what they have are either full of **** or stupid.

Comparing Stock Eliminator to a corner turning car is overly simplistic.

They didn’t make the rule to make **** “fair”. They did it because it’s STOCK and they chose to keep that part STOCK.

Not the same.

So stop with your whining and put on your big boy pants. Stupid rules are stupid rules.

Truth is truth.

You should red X your dumb self. Or better yet, BLOCK ME. I get tired of clowns talking ****.

Bad rule, bad class. Simple as that. If the OP wants to run the class then who cares what the “real world” experience is? The OP will need to PAY to out innovate everyone else if he wants to win.

That burns through money. Fast.

I agree, and using the intake manifold to add parity to a class with multiple manufacturers is about the worst way to do it.

 

[Fast340cuda]

This information is immensely helpful. Thanks.

What type and size headers are you running?

TTI stepped. 1 5/8 to 1 3/4

 

[RustyRatRod]

Ask em what the .050 intake duration is. I’m betting you won’t get an answer. Maybe @GTX JOHN can chime in.

Yeah that ain't limited. That's where cheater cams come into play. I've built lots of dirt track engines under the stock lift rule.