Who knows what and what have you done.
I am rebuilding a 460 for my bronco. I want the beast to go fast and have tons of off road potential.
I want to know what i good compression ratio would be to go with.


Also,
What is the highest compression you can have WITHOUT having to go to higher octane fuel? I was told 8.9:1.
What do you think?

Thanks.

 

Hi,

what year is your 460 engine?
Maybe it's possible to install some heads from a '69 460 cid, they have huge valves and a smaller combustion chamber.


The highest compression you can have without having to go to higher octane fuel?.....yes, I think it's arround 9.0:1
:-)

Jens

 

[updated:LAST EDITED ON 10-Dec-02 AT 11:29 AM (EST)]Okay I will go for this agian since my reply didn't show up last night.

I run 10.5:1 KB flat top pistons in my 460 and it has no problem running on 92 octane.

I run a Performer cam in it so all of the power is in the low range 1000-5000rpm and has all the torque you might need.

I have the motor in a 7000# flatbed 4x4 and it will run 94mph in the quarter.

I did have the motor in a '79 Bronco and with 3.50 gears and 33" tires and we would race rice grinders with it a always beat them at 135+ mph.

 

Are you saying you run 10.5 to one compression in your 460 with just a modified cam. and have no problem with predit(pinging) Is you timing adj all the way advanced or backed off? assume you have changed the timing chain gears to correct. what head are you running.

I have a 460 with d3 heads and just bougt c9ve heads but am told I will have problems on low oct gas above 9.1 and will be closer to 10 to 1 with the new c9ve heads and my existing pistons.

Greg
74 crw

 

[updated:LAST EDITED ON 11-Dec-02 AT 01:03 AM (EST)]Okay here's my motor

750 Carter AFB
Perfomer Intake
Perfomer Cam
1.7:1 Roller Rockers
KB 10:1 .030 bore Pistons
CJ (truck) connecting rods
Every thing has been balanced

I run it with 10 degree initial timing and has a stock distributor in it that has not been messed with.

The same pistons I use (KB-137) with the C9VE heads will give you about 11.7:1 which would definetly not work on pump gas. Here is the 460 piston page on KB.
<http://www.kb-silvolite.com/page48.htm#SECT4>

I think I am right on the edge as far as gas goes, becuase even if I drop to 89 octane instead of 91 it really pings bad.

I re-figured it and I have 10:1 compression not 10.3, or 10.5.

 

cool info thanks

If I buy 87 oct gas I wonder how a quart of alchol would affect my overall octane and problems with too hi of c/r?

74 crw

 

I forgot to say that I am running D3VE-A2A heads.

 

 

Of course y'all could not have to worry about the octane problem by moving to South Carolina where you can still buy 103 Octane at the pump.
:-)