Wnat octane do I need?

[MoparBill]

http://www.forbbodiesonly.com/moparforum/asset.php?fid=237695&uid=2193&d=1443361311

I'm just looking for thoughts on what fuel to run-
440, .030 over, KB236 pistons, 906 heads w/Manlet SS valves, Comp XHE .525 lift 275 duration, HP manifolds, 4 speed.

Any help is much appreciated!

 

[Lionized]

I run Chevron 94. No ethanol.

 

[Yatzee]

If your the type that doesn't drive great distances then a better quality fuel like Shell V-Power with no ethanol would be my choice especially if it's carbuerated. If you do drive it daily or on long trips, I'd use a mix of 50/50 regular and high test as this actually ups the octane rating and your fuel and costs less to operate without sacrificing performance or fouling. As Archie Bunker said regarding beer, you never really own the fuel, you just borrow it.

 

[Jackpot50]

I have about same motor but with aluminum heads and I run 93 because no ethanol, but rule of thumb 10.5:1 compression max for pump gas max

 

[moparcrazy]

Pump Gas on 10/5/1 is perfect the open chamber 906 :headbang::headbang: Nice !

i'm running the same cam as you but with 1.6 rockers not the factory 1.5 my
engine was dyno'd at 550 HP / 600TQ and i run Pump Gas with No Problem here in the Tree huger state of Cali where 91 octane is the Highest They offer and with Ethanol, so basically **** gas !

 

[Dennis H]

Similar build here. Mine runs on **** California pump 91. Tune it to run on pump gas or it will be a pia with additives etc.

 

[lewtot184]

10.5:1, iron heads, and no quench. i'm skeptical that it will run on pump gas.

 

[44070dart]

If your the type that doesn't drive great distances then a better quality fuel like Shell V-Power with no ethanol would be my choice especially if it's carbuerated. If you do drive it daily or on long trips, I'd use a mix of 50/50 regular and high test as this actually ups the octane rating and your fuel and costs less to operate without sacrificing performance or fouling. As Archie Bunker said regarding beer, you never really own the fuel, you just borrow it.

Whats this about 50/50 upping the octane rating ..never heard that before

 

[ws23jrt]

This topic comes up from time to time and i always smile about it.

For one ---it is so complicated that no end as to the correct octane needed can be properly answered without specific data on an engine and how it will be used.

The 95% of us that seldom drive our engines at the top end have little to fuss over this.

Their must be a "mythbuster" type test about this that would put it back on the back burner where it belongs.

Those that build and race engines know what they need --- for a street car --not so much--

One thing I have found that gives my cars trouble is ethanol. I found a place nearby to buy real gas and am happy to pay the high price for it. (my lawnmower has never run better and my old cars start faster and smell like they should.)