Ok guys help me out here I've seen 400's run good I've driven 400's that run good but mine SUCKS!!!!!!!!!!!! Now then the last 4 trucks I've had ran 429's or 460's anywhere from stock to radical the best one being a 429 dove block stroked to 460 with dove heads harlond sharp rockers stock pistons dooe intake.edelbrock 600 carb and a comp 4x4 extreame cam ran great!!!! now I have a 1978 f250 with a edelbrock intake and carb 600 cfm 60's front and rear and its like driving an anchor!!!!!!!!!!! the motor is a stock rebuild with 7000 on it but it is realy depressing to drive, awful fuel mileage and no power the timing is good as is everything else, it runs good as far as no miss or anything like that just no power and crappy fuel economy. HELP!!!!!!!!!!!!
i used to have a problem similar to that with my 351m with an edelbrock performer 400 intake and holley 600 carb... but i never really watched the gas mileage issue... what was wrong with mine was the secondaries werent opening on the carb and it would just drag when i would floor it and it was all around gutless... brought the carb to a guy in town and had it rebuilt and then it felt like it had power
i used to have a problem similar to that with my 351m with an edelbrock performer 400 intake and holley 600 carb... but i never really watched the gas mileage issue... what was wrong with mine was the secondaries werent opening on the carb and it would just drag when i would floor it and it was all around gutless... brought the carb to a guy in town and had it rebuilt and then it felt like it had power
I was going to ask if he had vacuum Secondaires on that carb? I have watched the what happens to a truck when the secondaires don't open. It was a guy running a 71 C10 with a mildly worked 350. His first run was ok, he ran the second and we saw his power and Torque fall flat on it's face. Found the vacuum secondaires were sticking.
__________________ Committee:a group of the unwilling, picked from the unfit, to do the unnecessary.
"Brutus" 1978 F-150 SC 4x4 BB460
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Stock rebuild with the stock heads, stock valve timing, stock cam, stock compression? That's all the stuff that's wrong with a 400 and if it's all stock, it will be a pig till that's fixed.
Stock rebuild with the stock heads, stock valve timing, stock cam, stock compression? That's all the stuff that's wrong with a 400 and if it's all stock, it will be a pig till that's fixed.
??? Doesn't sound like a stock 400 to me... My last stock 400 was a terror on the street, and I never changed a thing on it, even the 2V carb! Yeah, it lost a lot of power after 4000 rpm, but until then, tire smoke and giggles! You just need some diagnosis and fine tuning and all will be well again. Start with the little things.
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Mark in FL
restoretherepublic.com
Ya know I never even thought about the dist! that could be it ! the 600 edelbrock are all mechanical secondaries and they are working. the funny thing is I just put the same setup in a buddys truck and it runs like a stripped ass ape! the only thing different is his is a c6
Ok guys help me out here I've seen 400's run good I've driven 400's that run good but mine SUCKS!!!!!!!!!!!! Now then the last 4 trucks I've had ran 429's or 460's anywhere from stock to radical the best one being a 429 dove block stroked to 460 with dove heads harlond sharp rockers stock pistons dooe intake.edelbrock 600 carb and a comp 4x4 extreame cam ran great!!!! now I have a 1978 f250 with a edelbrock intake and carb 600 cfm 60's front and rear and its like driving an anchor!!!!!!!!!!! the motor is a stock rebuild with 7000 on it but it is realy depressing to drive, awful fuel mileage and no power the timing is good as is everything else, it runs good as far as no miss or anything like that just no power and crappy fuel economy. HELP!!!!!!!!!!!!
You sure it aint an ol´ worn out 351m, they are virtually identical the diference is internal(crank and pistons), and stockish 351m are lame dogssss
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"All right baby, see what I´ve got right here in my hands, I´ve got it right in my hands to score you baby, I think im gonna yank on a one town! Look Out!" Uncle Ted
Dang, the 351M in my '78 wasn't lame at all... I could pull anything with that truck ( much more than what it was rated for, anyway! lol) and it was quick off the line. Can still squawk the tires with over half a million on her... Getting ping when accelerating though, from stretched chain...
I would love to rebuild that one into a 400; It is a very well seasoned block!
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Mark in FL
restoretherepublic.com
dont get me wrong , I love the m too but my 351m when stock was a dog, ofcourse it had lots of miles on it...
__________________
"All right baby, see what I´ve got right here in my hands, I´ve got it right in my hands to score you baby, I think im gonna yank on a one town! Look Out!" Uncle Ted
im agreein with Goose, possibly see how much ur exhaust is restricted. i know of some bad 400's (hard to believe), i have a tempermental one, on a good day, it could pull the world if u could hook on to it, on other days, everyonce in a while, it will wanna give u a hard time.
well thanks guy's for all the help I think I found the problem,first of all I took a real close look at the dist and low and behold the jackass that stabbed the dist did it a 180 out then just walked the wire's around to fix it! so I says to myself self if this idiot cant put a dist in right what else did he screw up??? so I pull the cap off and the vacume advance is not hooked up the pickup coil and the pickup is retarded as far as can be and STUCK there. so I lubed it all up and reconnected every thing and retimed it and it runs much more gooder now!!!!! thanks gents for all your help
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400 it sucks!!!!!!!!!!!!
Uncle Ted
