LS7 heads on L92/LS3 427 shortblock w/4.070 bore
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From: Orlando Fl.
LS7 heads on L92/LS3 427 shortblock w/4.070 bore Has anyone tried to use or test fit LS7 heads on a 4.070 bore L92/LS3 shortblock. GMPP says the LS7 heads w/2.20 intake valve will fit on a bore of 4.080 and bigger most shops say 4.10 bore and bigger. I was also thinking if the 2.20 intake valve was too big that my local cylinder head guy could put in a smaller valveseat and use say a 2.18 intake valve that should clear the cylinder wall. The cnc LS7 heads flow 20-30cfm more then my cnc L92 heads from .400 lift on up and with the LS7s I could use the better flowing LS7 intake or a Fast 102.
The intake valve is not the problem. The exhatust valve runs into the top edge of the cylinder bore. A 4.080" bore will see the exhaust valve scrape the bore when started and run. The intake side is roomy. The nominal bore for the LS7's is 4.100".
We're working on a Stage 3 L92 port program. It'll use a 2.20" intake valve and have comprable flow to the LS7 heads. Still a month or two out on those. You'll see near LS7 performance for a lot less $.
Richard
We're working on a Stage 3 L92 port program. It'll use a 2.20" intake valve and have comprable flow to the LS7 heads. Still a month or two out on those. You'll see near LS7 performance for a lot less $.
Richard
Thread Starter
10 & 11 Second Club
iTrader: (2)
Joined: Nov 2002
Posts: 2,584
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From: Orlando Fl.
The intake valve is not the problem. The exhatust valve runs into the top edge of the cylinder bore. A 4.080" bore will see the exhaust valve scrape the bore when started and run. The intake side is roomy. The nominal bore for the LS7's is 4.100".
We're working on a Stage 3 L92 port program. It'll use a 2.20" intake valve and have comprable flow to the LS7 heads. Still a month or two out on those. You'll see near LS7 performance for a lot less $.
Richard
We're working on a Stage 3 L92 port program. It'll use a 2.20" intake valve and have comprable flow to the LS7 heads. Still a month or two out on those. You'll see near LS7 performance for a lot less $.
Richard
Richard
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Let me start by saying this. I completely agree, all of you L92, LS3 guys need another intake option. Especially you stroker guys.
But my point is this. In our world, any head is going to "outflow" it's intake. Anytime you lengthen the port, it knocks the flow down. I am so tired of hearing our intakes can't flow enough for our heads. Unless you are going to a huge sheetmetal or a ported single plane, your heads will outflow your intake. Get used to it. Deal with it. Can't change it.
But my point is this. In our world, any head is going to "outflow" it's intake. Anytime you lengthen the port, it knocks the flow down. I am so tired of hearing our intakes can't flow enough for our heads. Unless you are going to a huge sheetmetal or a ported single plane, your heads will outflow your intake. Get used to it. Deal with it. Can't change it.
