Edelbrock LT1 heads

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Mar 15, 2006 | 01:22 PM

#41

Jon A

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From: Everett

Thanks for the pictures, Jason. How do the runner lengths compare with stock?

Mar 15, 2006 | 05:52 PM

#42

SS MPSTR

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From: SoCal

Quote:

Originally Posted by jasonsny

The LT1 and LT4 manifolds have been casted and we are working on the running samples to be tested on a motor. I have a sample piece (images below), but I cannot run it as the core sand did not clean out of the EGR port passage on the underside of the plenum. This has been one of the delays as we had to work out a method of drilling out the passage after casting and it is the length of the manifold (big drill)!

This is also one of the hold-ups on my personal project also.

It took a lot of convincing from a group of us internally (GM LT1 enthusiasts) to get Vic to agree to build this manifold. I came to Edelbrock via a GM Performance Parts dealer and we have had much success with the LT1-to-LT4 conversions. As you may or may not know, GM has officially discontinued the LT4 manifold, so if you want a manifold with the material to port match lT4 or larger port heads, Edelbrock will fill that void and improve over stock while we're at it. Plus it looks cool.

http://www.edelbrock.com/advertising...s/DSC00774.jpg
http://www.edelbrock.com/advertising...s/DSC00775.jpg
http://www.edelbrock.com/advertising...s/DSC00776.jpg
http://www.edelbrock.com/advertising...s/DSC00777.jpg
http://www.edelbrock.com/advertising...s/DSC00778.jpg
http://www.edelbrock.com/advertising...s/DSC00779.jpg
http://www.edelbrock.com/advertising...s/DSC00780.jpg

I'll bolt up one of your LT4 test mule prototypes for ya...if you want to see what it does on a moderate to high output HR 383, send it out. I'm getting ready to pull off the heads on my 383 for a little more work, and I had planned on doing more to my LT4 intake too...

I assume this is being cast in San Jacinto (I was the architect for the foundry building in San Jacinto) or Torrance? I'll drive to either place.

Mar 15, 2006 | 07:58 PM

#43

96capricemgr

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Quote:

Originally Posted by jasonsny

.

As for the heads, the flow numbers on the Edelbrock LT1 heads are as follows:
.100 61 / 52
.200 117 / 100
.300 174 / 140
.400 220 / 167
.500 242 / 184
We found the peak at .500 lift to be about 16cfm better than stock, out of the box

Take into account a thicker deck; better valve springs; blending work in the bowls; cnc profiled intake port entries and exhaust port exits; heli-coiled intake and exhaust flanges. We feel that this is a great cylinder head at a fair price. Whether you need it or not is up to you.

We'll keep you posted on my results!

Thank you,
Jason.

So with minor port cleanup they flow better than as cast stock heads.

Helicoil and thicker deck are good though I know of nobody with deck strength issues on stockers. Valvesprings NEED to match a cam so IMO that is not an important point. The I/E ratio looks better which explains the single pattern cam package when nearly everything else available for these motors is dual pattern to make up for poorer I/E ratios.

I think it good if companies will actually develop improved parts. EVERYTHING I see about these is that they developed a part specifically to fill a demand and are willing to do that even though it is not a signifigant improvement. I would consider this as little more than a new stock casting equivalant. Let's give a stock head a little tweak with the grinder and compare, wouldn't that be more telling since these have been touched?