Magilla Gorilla

i have a stock bottom end ls1 that i will be putting a set of heads on with chambers opened to 4.0 bore.
that being said the ls1 head gasket is 3.950", and the gasket overhangs the CC bore by .025 on each side.
the 6.0 gasket is 4.020", and will clear the CC bore with no issue. i plan on notching the cylinder bore to accomodate the heads, just curious if there will be any sealing issues with the larger bore gasket on the ls1.

any input is appreciated. thank you.

vettenuts

iTrader: (4)

Not sure what you mean by notching the cylinder bore but it does't sound like a good idea. The gaskets will be fine. I ran those with my Darts. My current gaskets have a bigger bore due to the extra chamber work in my AFR heads.

Magilla Gorilla

what i mean by notching the bore is relieving the top of the cylinder bore to match the overhang of the CC bore. but only around the intake valve. im not sure if other people do it around the whole circumferance minus quench pad, but my objective is to unshroud the large intake valve only.
what i have done in the past is apply a coat of dykem to the approximate area of the deck that will be modified on the bare block, then bolt the head down using one bolt. i sharpen a very small allen wrench to a point on the hooked side and gently scribe into the deck, where the chamber overhangs. now unbolt the head and you can see how far it needs to be relieved. now lets assume the engine is zero deck. you would measure the height of the top ring land (between compression ring and piston deck). cut that number in half to be safe, and that will be how deep down the bore to notch. then with a carbide i approach the cut at a 45* angle .only very little material needs to be removed, but it gets rid of that step that protrudes into the path of air flow. i have done this on a couple sbc engines in the past, but those already had a notched head gasket. thats why i wanted to be sure of th head gasket compatability cuz i knew the stock would be too small.

bww3588

iTrader: (49)

i hope you know the stock LS1 has -.008 of deck clearence and if you notch the block you run the risk of losing your rings on the notch.

Magilla Gorilla

i have taken that into consideration. i was using zero deck as an example.
i will leave more than enough room to clear the top of the ring's travel.

novaflash2002

iTrader: (51)

forget the rings, i would worry about the coolant passage. you have about .200 play befor you hit the top ring travel. bigger valves dont always mean more power.

Magilla Gorilla

which coolant passage? i think you may be over examining it. im talking about very minimal removal of material here. the main focus is to remove the sharp step that protrudes in the path of incoming charge.
i dont see why the big valves wont make good power. i see people running l92 heads on 6.0's all the time w/ excellent results. i think all the big runners and valve means is less aggressive of a cam to make the same power.

novaflash2002

iTrader: (51)

so why worry about notching the block for 5 to 10 hp. trust me not worth it. i build engines for a living. i can tell you this, i know that you can make more peake power with a bigger valve, but with a smaller valve you can make more average power. more average power is more for a street car.