The Stovebolt Site Forums The Parking Lot Big Bolts any way to get more mpg out of 292 in '64 C60

Hello,
The 292 in my 64 C60 dump runs great but only gets about 3-4 mpg. I've gotten 5 or 6 in similar trucks with 366 v8's. I know its geared low(absolute top speed in 5th gear high range is 55)I am going to change to HEI ignition, and possibly change the carb to a one barrel holley that I used to run on an old 250. It used considerably less gas than the old rochester B model did.Idealy I would like to get at least 5 or 6 mpg out this engine If anyone has any ideas or sugestions I'd sure like to hear them. I'd hate to have to swap to v8 to get better gas mileage. Thanks, Mike

making sure the engine is in tune, no vacuum leaks, and the timing advance is working are biggies. hotter range plugs and lighter weight springs in the distributer advance mechanism is also helpful. aftermarket air cleaners are greatly better than stock units, but alot of guys insist on stock breather assemblies at the expense of engine efficiency. switching to an electric fan will help. that stock fan eats power. then look at the brakes to insure they don't drag, and----the easiest thing of all---check and maintain tire pressure. is that of any help? good luck, and if you do any of those things i suggested and it works, please post the results.

well gray your thoughts about the carb will help alittle bit on fuel econemy but it is going to rob power big time Koolkars suggestions are good ones as well you'll have to pick whether you want to stay as original as possible or want the economy on some of them on these big trucks alot of your fuel economy is effected by your transmitions gearing and the amount of weight your carrying around that dump bed is hurting your economy as well but all of the above are good suggestions and ideas and will all help at least a little bit and some alot.

I also agree with the good suggestions listed above. Something must be wrong with your truck tho. I have a 292 in a '64 C-30 1-Ton that I ran for 9 years. Fully loaded at 10,000 plus pounds, that truck would get about 14 or 15 MPG. It was pure stock, except for a slightly shaved head (done at valve job time), a less restrictive air cleaner and most importantly a Straight-Thru Muffler. These engines like to breathe and the muffler alone will make a big difference. I ran the shorter smaller straight thru GMC V-6 muffler that are hard to find now, but you could just use a glass pack. I'm also a big fan of the original 1-Barrel carb, but some carbs just aren't as good as others and you may want to try to change it. Also, I'm not saying that you don't, but how it is driven and at what points to shift at also play an important part. I'm a believer of keeping the crankshaft spinning (no lugging) and at the same time keeping a light foot on the gas.

Bill

Have you run a proper compression check? Better yet, a leak-down test if you can find someone with the right tool.

I'd start with a careful tuneup, as others have suggested, and check everything extra-carefully as you go. Set the advance at least as much as stock, and more if your ear says it's not pinging. In general, the more advance the better the mileage.

Fuel leaks, too. Watch the carb area while you drive it. You can sprinkle talcum powder around the carb and manifold and any gas leaks will mark it. A bit messy but a good leak-finder. (And talcum is way soft - a bit in the engine won't hurt, but don't sprinkle it in.)

George