ZeroTraction

iTrader: (4)

Building a carbureted ls1 for an autocross weekend toy and want as much mid range power I can get. Car will have a 6spd and bolts on, cam, headers, pulley, ported heads ect. Will a factory short block with milled AFRs at 61cc with a .040head gasket (good quench) be to much compression for 91 fuel? In Idaho it's hard to get 93 these days. I have not picked a cam yet. Thanks guys

Dragls

Contact Pat G for a custom cam to compliment your setup.

98znasty

I'm limited to 91 as well here in Tucson and I see a little knock on my setup(64cc heads .040 gasket and sbe ls1. Granted it's real hot here.

kossuth

iTrader: (12)

07NBSChevy

iTrader: (1)

Without more info, can't really say.
What head gasket bore size, 3.910"?
Piston Domed or Dished, CC's?
Piston Deck Clearance/ Piston out of Hole?



With a Quench of 0.035-0.040", 11:1, 91 Octane, and a good tune, you wont have any issues.

ZeroTraction

iTrader: (4)

Factory short block so pistons are .005-.010 out of the hole. Factory bore size head gaskets ect.....yes quench will be tight and compression high. I guess with conservative timing I should be fine

LSOHOLIC

iTrader: (3)

Lots if variables but...here is a very close SCR....
~61cc = chamber
~0 = piston head volume (no dome or valve reliefs)
~0.010" = deck clearance (piston out of the hole)
~3.910 = gasket bore
~0.040 = gasket thickness
~3.898 = engine bore
~3.622 = engine stroke
** = 11.589 SCR **

same numbers as above but with a piston 0.005 out of the hole.....
** = 11.438 SCR **

As others have said....DCR is what makes or breaks the octane requirements.

Will you possibly need to flycut ?

.

ZeroTraction

iTrader: (4)

No fly cutting. I'll keep it in the 220-low330s

poltergeist 02

iTrader: (65)