visual differances between stock lt1 and edelbrock
03-10-2004, 12:54 AM
#1
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Join Date: Jun 2003
Posts: 166
visual differances between stock lt1 and edelbrock
I am starting to pull the heads off the Z28 now to install the edelbrocks and have been compairing the intake ports.
at the intake port opening its basicly a port match done by a CNC machine, the restriction around the push rods is the same width between the two heads (about a thum width) even the port floor looks the same That is were the simularitys end. edelbrock made changes to the port roof, making it flat all the way to the valve stem, wile the stock LT1 head is lower and angled to one side of the port to help with swearl It would seem.
So the added air flow comes from the higher flater upper half of the port mostly. looking at the port flow it would seem there is a restricion to flow above .500 lift flow actualy drops off at .600
I beleve the restricion comes from the bump around the push rods. it make the port verry small at that area, one could probly grind alot of material from that area with out loosing any low end power or flow as the rest of the port is already larger than around the push rods.
On the edelbrocks I did some clean up were the CNC machning was done, rounded strate eges, blended and smothed, and I did remove a small amount from around the push rods (1mm or so)
If I can figure out how to post pictures I took some digital shots of the heads and will post them
at the intake port opening its basicly a port match done by a CNC machine, the restriction around the push rods is the same width between the two heads (about a thum width) even the port floor looks the same That is were the simularitys end. edelbrock made changes to the port roof, making it flat all the way to the valve stem, wile the stock LT1 head is lower and angled to one side of the port to help with swearl It would seem.
So the added air flow comes from the higher flater upper half of the port mostly. looking at the port flow it would seem there is a restricion to flow above .500 lift flow actualy drops off at .600
I beleve the restricion comes from the bump around the push rods. it make the port verry small at that area, one could probly grind alot of material from that area with out loosing any low end power or flow as the rest of the port is already larger than around the push rods.
On the edelbrocks I did some clean up were the CNC machning was done, rounded strate eges, blended and smothed, and I did remove a small amount from around the push rods (1mm or so)
If I can figure out how to post pictures I took some digital shots of the heads and will post them
03-10-2004, 02:28 AM
#3
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Join Date: Jun 2003
Posts: 166
I'm going to be using the edelbrock cam also with 1.5 rockers.
it was not clear on edelbrocks site on what ratio thay used to get .525 lift, when I called tech suport they said .525 was using 1.5 rockers. I will be quite pissed if the cam spec card says other wise because I already bought the 1.5 crane SA rockers, and I cant return them! The valve springs on the head are good for .600 max lift so I could have gone with the 1.6 if I wanted to but .525 should be good enough.
218 duration at .050 intake and exaust and .525 lift
it was not clear on edelbrocks site on what ratio thay used to get .525 lift, when I called tech suport they said .525 was using 1.5 rockers. I will be quite pissed if the cam spec card says other wise because I already bought the 1.5 crane SA rockers, and I cant return them! The valve springs on the head are good for .600 max lift so I could have gone with the 1.6 if I wanted to but .525 should be good enough.
218 duration at .050 intake and exaust and .525 lift
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