So I am getting ready to put my 390 together and am going to sit down and order parts soon. Being this is my first FE motor I was wondering what compression ratio I can get away with on the street using 89 octane gas. Im using Fairlaine 390 GT heads on this motor. Now in the past on my Chevy motors I usually could get away with 10:1 compression but I thought I read somewhere that FE motors are a little more prone to detonation.
Wes Adams FORD428CJ
Built Ford Tuff With Good Ford Stuff
03 F-250 Crew Cab 4x4 6.0 and 35's
64 Falcon 428FE
55 FORD Truck 4-link Rides on air with 428FE
2000 Yamaha V-MAX VMOA#4277
2000 Yamaha 700 Mountain Max
2001 Polaris 600 Edge X
2001 Polaris 500 SP
With proper ignition timing and cam timing, you should be fine.
Make sure you intake valves are not sunk into the head too far, that will make them run hot and ping.
Here in california, gas is bad, so i would recommend 9.1 to 9.8 for a driver, 9,75 to 10.2 with a hotter cam, over that you have to be very careful or have a reduculus cam for a driver.
1964 Galaxie 4Dr Sedan, 289, 3spd (re-installing OD soon), a Texas Sargent's Personal Car
1967 416 GT engine, BIBO Wide R TL
1968 428 'C', '69 SCJ heads, Gal Wide R TL
Oh and a Bicycle daily driver.
This message has been edited by TorinoBP88 on Apr 23, 2012 9:37 AM
No its going in a Model A coupe street rod in front of a C6. Cam is going to be an Isky 264 Mega hydraulic cam and it will have a dual quad Edelbrock intake with two 500 cfm AVS carbs unless I come up with the extra scratch to get a factory tri power setup between now and then.
My S code 390 in a 68 Torino liked Sunoco 93.5 back in the early 90's. I see the local 66 station's premium is 93 vs 91 most everywhere else in central Ia.
I'd have to look again, but I believe the owner's manual says use 100 minimum.