Built LT1

iTrader: (3)

Did a search but couldn't ascertain a definate answer.

Scoggin dickey offers a forged 427 LS3 shortblock and I wanted to know if the LS7 heads and intake could be matched without issues.

Link to thread:


http://www.gmhightechperformance.com...ne_blocks.html


BLOCK: LS3, ALUMINUM
Cubic Inches: 427 Crankshaft: Scat, 4340 forged steel, 4.100-inch
Rods: Scat I-beam, forged steel, 6.125-inch
Pistons: Manley flat-top, forged
Rings: Ackerly & Childs, plasma-moly
Rod Bearings: King Engine
Main Bearings: King Engine
Cam Bearings: Dura-Bond
Machine Work: Torque plate hone, deck resurface (as necessary), stroker clearance, balanced rotating assembly
Core Charge: No
Warranty: 90-day
Price: $3,999.95
Options: No

KingSS

iTrader: (1)

LS7 heads require a 4.100" bore or larger to work correctly.

Built LT1

iTrader: (3)

In other words, you're saying it will work just fine then? There's no other issues?

formula17

iTrader: (4)

Wont work, bore is only 4.060ish on an ls3. Intake valve will hit

Robin L

Well..........they might work But I would not try unless you are willing to take a risk.

What these guys posted is true, the LS7 heads are designed for the larger bore.

But.... I wondered just how close they are. I could not get a real answer from anyone.
I have a LS3 on the engine stand. So I thought "what the hell". I dropped a piston out of #5. I then bolted a L7 head on the block with an LS7 gasket. The intake valves clear by a bunch. The exhaust valve is within .020 to .030 from the cylinder wall. THe chamber also is larger than the bore but that doesn't hurt that much hehe.

As close as the exhaust valve is to the cylinder wall it probably hurts the flow just a little bit.

I might have to try it when I have some spare time.

Robin

Built LT1

iTrader: (3)

I understand what you're saying, but the LS3 bore is 4.100 per the web site I referenced.

So given that information, I'm just wondering if there would be any other problem(s) with that set up.

Robin L

The LS3 and L92 are 4.060.

And the intake has plenty of room.


Robin

JUNK

They use a 4.100 stroke crank, not bore. But this may work.............

Built LT1

iTrader: (3)

For whatever reason I was thinking the 4.100 was the bore size, not the stroke.

So it's either staying with ported LS3 heads, or like others have mentioned, it would depend on the limited 4.060 bore clearance--which is fairly minimal. Now I got it. LOL

Haans249

iTrader: (24)

This is VERY enlightening news you have. I've always wondered the same thing, but never had the ability to just plop a LS7 head on a 6.2L block. 20-30thou clearance is pretty tight. How much will that shrink once the exhaust valve is blistering hot?