Posted By: MoPar Jamie
Best combo for mileage? - 10/30/10 05:27 AM
Ok guys, this is mostly carb related but I also have a set of 302 heads at my disposal, the motor in my '86 5th Ave has bottom end issues.
The vehicle is my 1975 D-100 shorty pickup. It has a stock '83 318 2-v with under 100k backed by an A-833OD iron case tranny out of a '76. The rear is original to the frame, an 8 1/4 with 3.55 gears. I am running manual steering and no A/C.
Dry weight without a driver is 3600 lbs, as I took a load of breakage over the scales recently. I'm usually packing tools and parts that add around 100-150 lbs to that. Not to mention my weight that I wont mention.
At first I was getting close to 15 mpg not tuned. Its gone downhill because the re-manned BBD is starting to get cranky. It runs ok but rich and the main gasket is starting to seep.
Anyway I'd like to find the best combo for mileage. I'd love to see 18-20 out of this thing. Do I stick with the 2-v or go with a 4-v? I have a stock iron '84 360 4-v manifold at my disposal.
Now on my heads, is it worth it to throw on a set of "302" heads on an otherwise stock 318? Will I see any gains over my open chambers?
I want this thing to have some get up and go but do decent enough for me to be able to afford to drive it daily. Opinions?
The vehicle is my 1975 D-100 shorty pickup. It has a stock '83 318 2-v with under 100k backed by an A-833OD iron case tranny out of a '76. The rear is original to the frame, an 8 1/4 with 3.55 gears. I am running manual steering and no A/C.
Dry weight without a driver is 3600 lbs, as I took a load of breakage over the scales recently. I'm usually packing tools and parts that add around 100-150 lbs to that. Not to mention my weight that I wont mention.
At first I was getting close to 15 mpg not tuned. Its gone downhill because the re-manned BBD is starting to get cranky. It runs ok but rich and the main gasket is starting to seep.
Anyway I'd like to find the best combo for mileage. I'd love to see 18-20 out of this thing. Do I stick with the 2-v or go with a 4-v? I have a stock iron '84 360 4-v manifold at my disposal.
Now on my heads, is it worth it to throw on a set of "302" heads on an otherwise stock 318? Will I see any gains over my open chambers?
I want this thing to have some get up and go but do decent enough for me to be able to afford to drive it daily. Opinions?
PS yes the 302 heads will help you & been some good info on upping the valve size (iirc from 1.78 to 1.88 plus some bowl hogging (dont remem the angle) & staying w shim gaskets so you dont lose compression which require flat surfaces which you'd have if you did the 302's right but no telling about the block decks for flatmess & w 318 short block rebuilders being cheap I'd actually build one from scratch & get some good pistons & get quench & have a spot on eng from the ground up. W few cubes/alot of weight you need torque which means matched systems & parts/compression/quench so a higher compression will run on pump gas
... it is ruff typing with one handed .... my left hand got nailed by a circular saw. 