68 289 C code engine tips!

[Crs]

I'm in the process of getting my engine rebuilt. I'm looking for a healthy combo with excellent throttle responce that will give me the most out of my block without being a gas hog. I have 3.50 gears in the rear with a C4 2500 stall(I may ditch to smaller stall). I just sold my 393 stroker.....so i'm building my original 289. Thanks!

 

[Cobain03]

my mods are in my sig and i only get 10 mpg in town.

 

[Crs]

Are you still using stock heads? Is there anything with your combo that you would change if you could?

 

[JEE740]

Crs, what kind of MPG were you getting with your 393? I'm just curious, since people can have different opinions on what a "gas hog" is. Also, what kind of performance were you getting from your previous combo?

 

[Cobain03]

stock heads, but worked a little bit. there are slightly larger valves.

i have a weird situation where i think i have the wrong headers and i had to jack my engine up about an inch for the secondary tubes to pass the inner fender towers, also my hood scoop is bolted on with about 1 inch bolts sticking on the underside of the hood. i dont even want to explain why cause there is no resonable answer.

because of that i have major clearance issues. if those two items were out of the way, i would go performer RPM intake with performer RPM heads to match the specs on the cam (same as the performer RPM cam). i would put 3.50s in the rear (currently 2.80) with a 5 speed. the RPM package dyno sheet from edelbrocks website says 367 horse 340 torque. thats QUITE a bit difference lol.

 

[Crs]

On my 393 , i was getting 7-8 MPG normal driving with occasional flooring of the pedal. The person who built the engine said it was a 400 hp motor with a mid 12 sec capability...........................never took it to the track though!

Thanks for your input Cobain ! I was thinking about a Crane Energizer 272 or a similar Comp Cam, with my stock heads cleaned up and the comp ratio bumped up a bit . Maybe the Edelbrock Package might not be a bad option either........... but i wonder how fuel efficient it is?

 

[C0V3R]

An overdrive will do as much for you as any build ever will. Consider putting in an aod or a t5 at the same time if you can stretch the extra.

 

[Crs]

I will consider

 

[jadesville]

The C4 is what is killing you, I could only best 6-7mpg on highway with mine.

Overdrive, AOD or T5 will be a major improvement. Vacuum secondary carb (with an automatic), later model heads.

 

[Cobain03]

in all honesty, if your building for gas mileage, your building the wrong engine lol. get a 4 banger

 

[dennis112]

The 393 in my sig gets 14-15mpg with careful (boring) driving and normally around 11mpg with lots and lots of flogging--with a 1:1 ratio toploader, 3:70 gears, and 26" tall tires.

When I had a basically stock 351w in the 65' it got 19mpg using 3:10 gears.