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Discussion Starter · #1 ·
I have a 11 to 1 327 I want to put in my 67 ,but I am worried about what gas to run .
93 octane ,93 octane w/104 boost,or cam 2
this is a street car for weekend play .
cam 2 would be difficult to find when out cruising, I was thinking of the 104 stuff ,I could carry a case in the trunk for when I fill up ,
I just want to get some thoughts before I pull the stock 8.5 to 1 350 (not orginal)

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I'm running 10.7:1 on my 383, and set the timing to 10-12 degrees initial and 36 degrees toal by 2800. You should run at least 93, and set your timing to keep from detonation.
MSD also makes a timing control for under $100, that way you can adjust your timing up to 15 degrees inside your car. Plugs into your distibutor.
That way, when you are ready to play, add good gas and set up the timing a few degrees. When you go back to street, back it down. Cost is high at first, the inital $100, but can save you motor parts later.
I plan on ordering one.
hope this helps.

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383 Speed-O-Motive stroker kit with Speed Demon 750, RPM intake,Proform HEI dist.MSD6a box,World Products Sportsman II heads, ported and polished with 2.02/1.60 valves,64cc,TRW forged pistons with 10.7:1 compression, Comp Xtreme 284 cam,Crane pushrods, Comp Cam 1.6 full roller rockers,ATI damper, 40 series Flowmasters, 4.11 gears with TH350 and 3000 stall.Powertrax NoSlip Locker
 

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All of my cars have 11:1 except the LS-6 which has 11.25:1. I've found they run best w/5 gallons of Cam 2 leaded 110 octane race gas per tankful of 93 unleaded. The 104+ octane booster never seemed to get rid of all of the ping. I don't drive them that much so this works great and I can run full advance.
 

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Another thing to consider: What type of cam are you running? If the cam has a fair amount of overlap and/or duration then you can get away with higher compression on lower ocatane gas. Consider a typical 292 Street/Strip cam with about 0.5" lift and 110 degree lobe separation, it has fair amount of overlap and there is a definite bleed down effect. Detonation is all about temperature and cylinder pressure. A typical mild street cam will have less duration and overlap, therefore will begin building cylinder pressure earlier than the more radical cam. In the case of the mild cam, the dynamic and static compression are very close to each other, meaning that when the piston is at the bottom and begins to move up, the intake valve is nearly closed and cylinder pressure begins building immediately. In contrast, the dynamic and static compression can be very different on a radical cam. Since the intake valve stays open longer, the piston may not begin building pressure until it is farther up during the compression stroke. The net effect is that the dynamic compression is lower than the theoretical BDC compression. In the case of my 406, I run a CompCams 292H, and 11:1 compression on 91 octane pump gas. Yes, I do have aluminum heads. BUT, before I did my head swap, I was running 11.7:1 with cast Iron heads, no detonation. So... moral of the story is, what cam you run makes a big difference on what octane you can get away with. The more mild the cam, the higher ocatane needed to sustain the higher compression.

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Shawn Peterson
1969 Z28, 406SB
http://www.geocities.com/corsican69
 

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Shawn, that was a good explaination.
Thanks
Joe

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69 SS396 Clone, B&M TH400, 3.55 12 Bolt Posi, Blue w/White Z28 Stripes, Chrome Rally Wheels
[email protected]
 

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GeorgeZ28,

Old Dominion Speedway sells race gas and shouldn't be more than 15 miles from you. There used to be a speed shop at Rte 28/Sterling Blvd. that sold Cam II, not sure if it is still there.
 

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Discussion Starter · #8 ·
I guess I'll have to drop it in and see what it wants! I dont know what the cam is in it
If I pull the cam and get the #'s can anyone I.D. it for me?
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stock? 67
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[This message has been edited by 4 speed (edited 02-15-2001).]
 

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Don't forget combustion chamber shape will play a role on what kind of compression you can run with pump gas . . . there's a little more to it than compression ratio, timing and cams. I hear that zero decking a block can be worth a couple extra free compression points without needing a change in fuel, timing, etc. Something to do with a higher velocity in the quench area creating a cooling effect that in turn reduces detonation ? !? Don't ask for more of an explanation that that from me though . . . I know just enough to be dangerous.
 

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GeorgeZ28,

Hey, I live in Centreville, where in Chantilly do you live? You may have seen me around in my '68, it is dark green and sports some torque thrust II rims. If you have any mechanical work you can't handle, I know a GREAT mechanic. He is in Chantilly. Nice Camaros by the way...

70RS/Z28

yeah, that shop is still there, it is called Auto Sport. I have some friends that they have ripped off bigtime (saying they were putting in new aluminum heads and rather putting in some old grungy 1970's casting, 76cc heads while the aluminum heads this guy bought have mysteriously disappeared). They are also overpriced.
 

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I don't know about Virginia, but in Dixon, Illinois I get Sunoco 110 octane gas from the local heating oil distributors or from the local FS. (Farmer Service). The last 55 gallon drum cost me $200. I mix about 50/50 with 93 octane pump gas.
 

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Hey does any one know if this is true, a while back a friend of my dads told me that putting moth balls in you gas tank will give you 10-20 points, he said they use to use it alot in the 60's. Seeing how i was -23years old in the 60's i dont know? If anyone knows if this is true where can i get these moth balls????
 

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I ran a factory 340hp 327 in my Vette for a while. I thought it wasn't pinging and everything was fine. it made about 20,000mi and was literaly worn out the guides were destroyed there was over .010 wear in the cylinders the thing was just dead. I don't thing it is worth the effort.
 

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Does any body know the combinations for mixing av gas with premium to get decent results?


have any friends that work at the airport?
I do he-he but dont know how to mix it?

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69 Camaro 327/Th400
Deluxe Houndstooth
Still got the protecto plate, build sheet, owners manual,inspection sheet from dealer, and a reciept for an extra key on date of purchase from dealer.

Visions of wheelstands in my head
 

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AV-GAS is not the best thing to run. For starters it is a low lubricated fuel. Secondly, it was formulated to for a high altitude, low oxygen air. This fact is compouded if you run NOS.

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Mark

1992 Firebird 355/Six Speed (Soon to be LT1)
1991 RS 350 / 700-R4
1987 Toyota Pickup 383 / 500 + HP 10.963 @ 119.95 Slicks / 11.997 @ 114.23 Radials
"Speed KILLS, so drive a FORD and live forever!"
http://personal.lig.bellsouth.net/~racer383/

Member of the "unwanted" 3rd Gen group.
 

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Just to let you guys know, many people have the dreaded vapor lock. I did... My car was only driven during parades. If you can imagine the long periods of idling around in a parade with big cam/compression on my 327 in 56 chevy. So anyway, my point is that I had tried 3 different fuel pumps, and routing of fuel lines and carb spacers, etc... the problem is that AV gas has the low tolerant to heat. So if you run the AV gas like I did, be aware that more than 30 minutes of driving, will cause vapor lock.
I mean there will be zero fuel pressure and you starve the carb. just a word of advise learned through my experience.
 

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The deal w/ the old "mothballs" trick is that the original ones were made out of napthalene and not para-dichlorobenzene as most are nowadays. Napthalene is an octane booster and it will disolve in gasoline and help raise the octane somewhat. pdq67
 
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