400 Mod options?
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From: On a farm in Alberta.
400 Mod options?
Hi i have a 400 short block in my 78 ford. i'm lookin to build another one up with a lil bit of performance parts but yet not make it a complete gas gusiling pig. mine original motor blew up and i found a redone block with flatt head pistons, comp cam, crank, and roller rocker lifters and some otehr goodies for $1400 canadian... i was wondering if i threw a set of cleveland aluminum heads on it with a edlebrock performer intake and 650 cfm carb will my gas milage be horrible? i was also goin to throw a set of ehaders and 3inch highflow exhast to make it breathe abit better... anotehr thing is would i be better to throw a 302 out of a 72 F100 and build that one up or stick with the 400?
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From: fargo, nd
what is your "gas guzzling pig" standard? is the truck 2wd or 4wd? what rear end ratio? ive heard of 460's in 2wd trucks with 2.75 rears driven conservatively getting 18 mpg empty... and 302s in 4x4s with fuel injection and all the newer stuff getting 12 mpg empty... it all depends on the build... if you build it for power, dont expect economy... if you build for economy dont expect power
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From: On a farm in Alberta.
its automatic and a 2wd... the parts list i have in the first question, would that give me like 12 mpg or more? i have no clue what the gear ratio is because on the door frame and door where the sticker would bem is peeld off so i can't tell u the gear ratio
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From: fargo, nd
if you have it tuned right, with a 600 cfm edelbrock carb and about 9-1 compression, and a mild cam, you could probably do 15 mpg. if you put a bigger cam in your mileage will suffer as will your low end power. my guess on rear ratio is about 3.54, but there should be a metal tag on the rear axle thatll say for sure. just post the numbers from the tag if you want to know.
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From: On a farm in Alberta.
for 9-1 compression , u can still run like regular pump fuel for that or already ahve to switch to premium? i live on a farm so i run dyed gas and it seemd to make no difference from runnin premium and dyed gas, it ran proper and everything, i was just wondering with that compression could i still run dyed gas?
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From: fargo, nd
yep 9-1 should be fine for 87 octane if the timing is set for it.. i dont think id try 85 octane though. my stock 1986 302 had 9.2-1 compression and had no gas issues, but had computer controlled timing.
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From: On a farm in Alberta.
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From: fargo, nd
well... you should be good then as long as the cam you pick isnt too big... should be able to get 15 mpg pretty easy on the highway driving conservatively, and around 10-12 in town
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From: fargo, nd
its the body that its in that makes the mileage suck. if it were in something light and aerodynamic with the same rear ratio- like a mustang or pinto or something, it would be able to get 20 mpg highway and 15 in town, which is about all you can expect from a v-8. my old 1986 grand marquis with a multiport injected hydraulic roller cammed 302 and overdrive transmission would get about 18 on the highway and 12 in town. im building it into a 347 stroker, aluminum heads and edelbrock carb, and putting it into a 1975 ford maverick, and i expect it to get around 20 on the highway and 15 in town driven conservatively, even with the extra 45 cubes- just from the weight and shape differences
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From: western montana
Darrin...it sounds like you might want to look for another type of rig...
I know the gas prices are raping us now and our trucks are getting more expensive to drive but even with the new lighter trucks with new technology...a 1/2 ton 4x4 often gets less than 17 overall and 2wd with a v/8 around 20 I think...not sure. Some can get 15 or a bit more out a properly built 400 in a 78 1/2 ton 4x4...and a bit more in the 2wd so it's somewhat comparable....and the $500 truck payment you don't have to pay buys a couple gallons.
the 302 is not a mileage engine in a truck...you get get about the same or worse mileage and have less performance to boot. The 300 isn't much better either...I had one in a 89 4x4 150 4x and it ave 15 or so with something like 308 gears and a 4 speed.
I don't think theres a happy answer for you on this topic.
I know the gas prices are raping us now and our trucks are getting more expensive to drive but even with the new lighter trucks with new technology...a 1/2 ton 4x4 often gets less than 17 overall and 2wd with a v/8 around 20 I think...not sure. Some can get 15 or a bit more out a properly built 400 in a 78 1/2 ton 4x4...and a bit more in the 2wd so it's somewhat comparable....and the $500 truck payment you don't have to pay buys a couple gallons.
the 302 is not a mileage engine in a truck...you get get about the same or worse mileage and have less performance to boot. The 300 isn't much better either...I had one in a 89 4x4 150 4x and it ave 15 or so with something like 308 gears and a 4 speed.
I don't think theres a happy answer for you on this topic.
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From: fargo, nd
thats pretty much what i said... about the best you could get out of your chosen vehicle is 18 mpg... if you want economy- get something smaller, lighter, and more aerodynamic, not a brick with wheels 