New guy here with a question for ya's. I'm setting up a 292 with a 700r4 behind it. I want to calculate and install the best rear end gear (presently 4:11). I found a "calculator" so If I know the best RPM I can figure out the best gear, mainly for mileage. So, what would be the best RPM for a 292, to shoot for, for cruisin about 70 MPH? The engine is basically stock. I am also trying to figure out the best carb for mileage. Presently, I have a Weber 32/36 DGEV200 12091 ser.430 I am told a Carter YF for a 300 Ford is a good/better choice. I'm just hesitant to go back to a single barrel. (Am I wrong?) This is all in a '64 GMC van. Driving it, altho a ton of fun, is like pushing a barn door down the road. I know any sort of mileage is a struggle to get but, while I'm setting it up, I'd like to do the best I can. TIA!! Chaz
Economy and 292 are not things that come up much in these forums. Most people here are leaning toward ringing more HP & RPMs out of them and a lot of that throws mpg out the window. These are engines with a different purpose. 292s have always had the gas guzzler reputation at was as compared to their little brothers. I believe it is possible to build a little stronger low end 292 for truck use that can get decent milage. I have been gathering parts and am ready to test my idea. I will use a 700R4 from a '89 GMC 2500 4x4 in my '68 C20 flatbed. It has a 3.55 Dana 60. I have a Crower low rpm cam that should help. Tom sells one too. I think the stock head & valves will be fine as this engine will rarely if ever see 3000. I have a set of 9.5 to 1 pistons. I will use late 80s GM TBI. It is a plan and nothing proven yet. Hoping to run it about 2000 or a little below. My plans tend to take a while.
"I wonder if God created man because he was disappointed in the monkey?" Mark Twain
Good info Beater. I am very aware this is not the engine for mileage but, it's what I got and I hope I can get some sort of decent mileage out of it. 12 mpg is hard to take, and what makes it worse, I love driving this thing. I want to get the best I can and I may as well do what I need to now. I have a friend that did some swapping of a VW TDI in a '70 Ford full size truck and claims 34 mpg. True or not, I can not say but, I'd bet at LEAST high 20's. I don't want or like diesels but one has to think about it. Thanks for all the input and your time to do so. I'd like to hear about what you get when she is on the road. Thanks again. Chaz
Chaz, I don't get stuff on the road very fast. Keeping stuff on the road keeps me busy along with being the one old man power company, water works, septic service, a two mile road maintenance crew.
Just a hint about the GM TBI the ECM from a 90 degree V6 (4.2) will work on our sixes. The rest if the conversion with junk yard & off the shelf parts is pretty simple. You might have to have someone tweak the ECM for best results. Again this is more from what I read than what I have done other than collect everything. About 16 years ago we put a temporary TBO on the 270 GMC in my pickup for a demo. It was run by a mega squirt unit. I had dome prep to add sensors and places for connections but we had in running in abider 30 minutes.
A couple of 292 mockup pictures with a Firebird turbo thrown in. (the original plan.)
"I wonder if God created man because he was disappointed in the monkey?" Mark Twain
First you'd have to match all of the components to the kind of performance you want. My goal is a better truck engine than a stock 292, which is a good truck engine. For the first go around I won't use the turbo until I can see what the cam, higher compression , and TBI do. But yes I think with a basically stock 292 with some forged pistons a turbo and TBI would improve performance not sure about milage. Stuffing more air & fuel in it likely would not give better milage except you might not be working it very hard. Built for higher rpm who knows?
"I wonder if God created man because he was disappointed in the monkey?" Mark Twain
