I'm at 10.5-1, I use 93 on the street,and turbo blue at the track,100-110,alot depends on the cam and your timing also.

------------------
Bob West
1972 Malibu
454+
TH350-3.73's
3900 lbs.
1.79 60 ft.
12.06 @ 112.89

 

The motor setup is crucial.

with right at 10:1 you should be fine with 93 octane any where you go.

Be sure the total timing is below 40*BTDC. Most run a 36*, that's a good goal to tune for.

Keep an ear out if you have a car full of friends and are racing up hill.

-Also a don't be too lean on the A/F ratio.

------------------
71' 3880# with me. Big Block 402, Merlin oval heads, 10.2:1CR, TH400, 3.73 posi,
1/8th: 8.0 @ 88mph
BEST 60': 1.85 w/street tires.
BEST 1/4: 12.5 with 1.89 sixty foot (street tires)
BEST MPH: 109mph

Picture of me roasting the tires and other guy stuff
Video of me staging (smoke of course)

 

Robert, cam is pretty medium, nothing extremely heavy but you know its there. Timing is 8 degrees advance, not sure of total.

 

Hmmm, well, d**m california smog law. The highest octane gas i can get at most pumps is 91 in the bay area. I might have to invest in an octane booster company.

 

I run the local 91 octane in my daily driver 406 with 10.4:1 compression. Tight quench height, polished surfaces and 36° total timing have me operating with no detonation.

------------------
67 Nova 3475# daily driver
10:1 406, 700R4, 224° Comp cam, RPM and a Q-jet - 11.76 @ 116
64 Chevelle Road Racer
67 Nova Wagon under construction
65 Corvette Road Racer

 

Excellent, thanks for the info guys, that satisfied any doubts or questions that i had.

 

If you go to my technical links site at www.inccn.net/jackstandslinks.htm , you will find several ariticles and/or links to octane issues and compression issues. Too many to list here.

Enjoy...and good luck

------------------
Steve Jack - ConceptOne Pulleys and Brackets / Engineering & Marketing Technologies

[This message has been edited by HOTRODSRJ (edited 03-10-2002).]

 

I've run everthing from 87 to 93 octane in my 67 BBC w/10.25 compression and a mild cam for close to 14 years now. Never had a problem.

------------------
TC Gold #92/ACES #1709
67 SS & 67 Elky
Dale's Place
Team 67
Midwest Chevelle Regional Governing Council
Integrity: If you have it, it doesn't matter - If you don't have it, it doesn't matter.

 

Now, what types of heads are these? Fe or Al?

 

They are polished and ported camel hump heads. Fe.

 

Would 10.5:1, with valve relieved pistons, iron heads, and a .040" quench on 91 octane be okay?

I want to lower my quench by buying shim gaskets, and if I do it'll raise my compression quite a bit.