I'm thinking of pairing up the L92 heads with the Katech block. I could go with LS7 heads but they are over twice as expensive. Plus I'm running this car on the street and the cam I choose will probably not breathe well above 7K RPM so I don't need a light, high-revving valvetrain.

However, I'm worried about the combustion chambers of the L92 which are designed for a 4.065" bore. The Katech block is 4.125, so the head will 'overhang' the bore by about 0.030".

Is this a big deal? Are there any downsides?

-ch

 

We put a set on LS7 no probelm.

 

If you had to guess--in terms of a percentage--what am I giving up in terms of performance over a true LS7 head combo? Again, I'm not going with a huge cam so high-RPM max power is not a big deal. I'd like to see over 525 at the wheels through an IRS.

-ch

 

Save the money and just do a 416 with L92 heads/L76 intake. You will meet your goals.

Or do this:
https://ls1tech.com/forums/showthrea...ighlight=shirl

Make a 427 from an overbored L92 block (.015" overbore) and 4.1" stroker crank: The factory bores were straight, no problem. If you don't want to go all the way to 4.100" on the L92 bore, why not go 4.080" with a 4.100" stroke and you get a very nice 427 cid...
Shirl Dickey

 

Yep, I know there are options. I just want to know what downsides there are to running a head that combustion chamber overhangs the bore.

-ch

 

If he heads are designed for a bore that's smaller than the Katech bore already is, how will the combustion chamber overhang the cylinder?

 

I have a suggestion. Bolt the bare L92 heads on your bare block and scribe the cylinders onto the deck of the heads. Then have a trusty head porter match it up.

 

Not a bad idea...an even better one if I'm getting the heads ported anyway.

What I'm wondering is if the overhang will cause any 'problems' i.e. quench issues, etc.

If I was unclear, let me clarify: the heads are smaller than the bores. The heads will overhang the bores.

-ch

 

DOUBLE POST.

The forum is acting very weird today.

-ch

 

The difference is so small that the head porter wouldn't need to use a carbide to rough it in. He can polish it out to the bore easily.