based on what dennis, lou and I have I'd say you could make it to 10.5 ish or somewhere around there. my cam has more duration than yours too....

just out of curiosity, did you mill the head or the block? I don't have a preference, but it seems like most people here prefer decking the block.

We trued the head which needed 11 to make it flat (64.5 cc camber) We also plan to take 20 of the block to bring the pistons to 10 in the hole and 10:1 CR.

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67Cuda,FAST EZEFI,340cu,CR=10.25,RollerCam&Rocker (XR268HR,#20-810-9)(#1622-16)(EddyRPM#60779,#7576), (MSD6AL,#6425) A904, GearVendorsOD, 8 1/4,3.55:1, ClassicAir

okay.

I took .1 off of the head and if I remember right .045 off of the block for 10.4 to 1. got the moly rings too.

I also had a ton of other work done to the head.......but thats another topic.

also not to beat the additives to death but you can mix up some moth balls in your gas and it will raise the octane a a few points

From April 2007 Discover Magazine:

Neurophysiologists find that inhaling the solvent toluene, or HUFFING,INCREASES DOPAMINE IN THE BRAIN in a manner similar to the effects of cocaine or nicotine

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

If you wish to destroy your engine, following this mythical advice is a great idea.

Otherwise not.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

You can always just add propylene oxide.

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Official Cookie and Mater Tormentor.

Hey Bagel how fast do you think my car would run with a mix of 110 Sonoco and a twelve pack of Bud. Thanks Ron Parker











Bagels Juiced Im Bamboozled

BUD!.....if you put marijauna in your gas tank you will clog the filter. Man you rednecks gotta learn how to roll......\

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Yeah....Im the one who destroyed this rare, vintage automobile.....

Has anyone thoght about a head gasket thicknes change to help if the CR is too much? Just a thought.

Hell Sandy I was talking about putting the Bud in the driver and Racing. Im a Ga Redneck so you know Im aint smart. But We are Rednecks and have some Bad Asz Slant Race Cars. Who Wants to jump on us. Yea Jump Who Is the frog. Thanks Ron Parker








Bagels Juiced Im Bamboozled

its been done.

An issue that seems to be missed quite often about compression, cams and octane is how they actually affect each other verses what we want. Running a bigger cam will allow higher compression to work ok for NORMAL driving. To run the engine hard enough to actually get the power out of it that it is built for will require enough octane and the correct spark advance. Backing off the timing can help some but will cost more power than running a lower compression ratio would with the correct timing. There is just so much that a given octane will work at without detonation. If your combination bleeds enough pressure at low rpm to allow high compression with low octane, it will not (should not) be that way in the peak torque range at full throttle. You will likely have a problem when it is run hard, and thats the whole point of a hot engine. The idea that "it only pings when you get on it" is OK has always baffled me. It is not making near the power it could when that happens and backing the timing off by more than a few degrees, maybe 5 at the most, will really cut the power output. In the end: timing lead matches chamber design, squish clearance, stroke and rod ratio, not compression ratio or octane. Compression and cam work together, bigger cams need more compression to have decent torque range. More compression will make more power with any cam, given enough octane. Octane needs to match peak pressures and temperatures present before and during the burn. The temp has to do with the rate of compression, not just the pressure. So too high a ratio can cause problems that other changes will not fix. It is better to build more cylinder pressure by complete filling, slower compression and burn the charge completely verses limiting the pressure with poor filling, compressing it faster(higher rate - ratio) and not burning it completely (less spark timing). Dual purpose? Show or race car? Build it to your dreams and buy the fuel needed or detune to get by for short trips and retune at the track. Keep your foot out of it on the street and realize it is going to run hot without the proper timing.

You might want to read through some Popular Hot Rodding Articles while you're at it:

Be The Camshaft Expert

Compression Comprehension

Compression Ratio Tech - The Power Squeeze

First iwant to say HI. I'm new here, I have an 87 sl6 pickup. I"m in the process of making it EFI turbo 5speed. I've cruised around here before and just saw this thread. I'm surprised nobody has mention the option of E-85 if its available in your area. It has an octane rating of 105 and its cheaper than 87. You do need to worry about erosion of rubber seals in things like fuel lines and fuel pumps, but if you put in a new fuel line and electric pump all will be solved. you just need to jet the carb a little larger. I plan on running it in my pickup once its finished. I have my own still to make it as well. If your interested in the alcohol option you can check out http://running_on_alcohol.tripod.com/index.html thats where i got my plans and learned a lot about alcohol fuel.