Some questions about 400 blocks
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Car: Trans Am
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Some questions about 400 blocks
Hey guys,
First off a local mechanic told me that 400s are really only good for torque, Said most of em were made for trucks. I was figureing more cubes more horsepower, am i wrong here? He said it would be a better idea to just build a 350. But i dont want to do that. Is the 400 aftermarket stuff really that much more money, because i would much rather build the 400. Everyone has a 350 it seems. So i guess my question is the 400 a waste of time and money or am i gonna love it? im lookin for 425-450 horses. Sould i just build the damn 350? thanks guys,
Joe
First off a local mechanic told me that 400s are really only good for torque, Said most of em were made for trucks. I was figureing more cubes more horsepower, am i wrong here? He said it would be a better idea to just build a 350. But i dont want to do that. Is the 400 aftermarket stuff really that much more money, because i would much rather build the 400. Everyone has a 350 it seems. So i guess my question is the 400 a waste of time and money or am i gonna love it? im lookin for 425-450 horses. Sould i just build the damn 350? thanks guys,
Joe
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The heads, cam, rods, intake, carb, and exhaust that came on small block 400's was the stuff of low RPM torque.
Get rid of all that, and you've got yourself a barn burner.
Start with a Motown shortblock, you've got the stuff capable of real power.
Get rid of all that, and you've got yourself a barn burner.
Start with a Motown shortblock, you've got the stuff capable of real power.
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Sounds to me like your "mechanic" thinks you have one, and is trying to talk you into gifting it to him for some kind of a sweet deal.
He's right in part; in factory trim, they sucked. The factory set them up for low-RPM grunt.
But that has nothing to do with what you can get out of one in a performance application. Put a set of heads on one that breathe, and a cam that does more than just crack the valves open for a few degrees, it's amazing what they'll do.
Parts cost is pretty muich the same as for an otherwise equivalent 350. In fact, alot of the parts ARE the same as for a 350.
If you can find one, build it.
He's right in part; in factory trim, they sucked. The factory set them up for low-RPM grunt.
But that has nothing to do with what you can get out of one in a performance application. Put a set of heads on one that breathe, and a cam that does more than just crack the valves open for a few degrees, it's amazing what they'll do.
Parts cost is pretty muich the same as for an otherwise equivalent 350. In fact, alot of the parts ARE the same as for a 350.
If you can find one, build it.
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Re: Some questions about 400 blocks
Originally posted by USMC RCT
Hey guys,
First off a local mechanic told me that 400s are really only good for torque, Said most of em were made for trucks. I was figureing more cubes more horsepower, am i wrong here? He said it would be a better idea to just build a 350. But i dont want to do that. Is the 400 aftermarket stuff really that much more money, because i would much rather build the 400. Everyone has a 350 it seems. So i guess my question is the 400 a waste of time and money or am i gonna love it? im lookin for 425-450 horses. Sould i just build the damn 350? thanks guys,
Joe
Hey guys,
First off a local mechanic told me that 400s are really only good for torque, Said most of em were made for trucks. I was figureing more cubes more horsepower, am i wrong here? He said it would be a better idea to just build a 350. But i dont want to do that. Is the 400 aftermarket stuff really that much more money, because i would much rather build the 400. Everyone has a 350 it seems. So i guess my question is the 400 a waste of time and money or am i gonna love it? im lookin for 425-450 horses. Sould i just build the damn 350? thanks guys,
Joe
your mechanic is obviously ill-informed to performance motors.
find a diffrent mechanic before you start building your motor.
almost every bolt on part, from intake to heads to cam works with the 400.. the only diffs are:
heads and head gaskets need "steam holes" you can add these with a hand drill or pay a machine shop $30 to do this.
the balancer and flywheel/flexplate are external balance. you need 400 specific ones.
other then that, its just a small block chevy, and everything works on it. its not "special". parts dont cost more (except for 400->T56 flywheels.. ouch.) people just spout their ignorance when they dont know the answer, but they feel they must tell you somthing because they're a mechanic.
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Car: '83 Z28, '07 Charger SRT8
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In factory trim, yes, they were torque motors. They were designed to pull tree stumps or 5 kids and their junk on vacation, not to run 12's.
But its a big bore and big stroke. Get some preformance heads, intake, pistons, etc... in there and watch it start skinning every 350 on the street.
But its a big bore and big stroke. Get some preformance heads, intake, pistons, etc... in there and watch it start skinning every 350 on the street.
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Car: Trans Am
Engine: 305
Transmission: 700r4
thanks guys you just made my day, oh and hes not my mechanic hes just some shmuck who sells old chevys and parts for them and fixes late models on the side. I was looking at the holley systemax II system for a 350 build up but how would that perform on a 400? It says its for a 350 so if that setup wont work for me do you guys have any suggestions? This is my first engine build up so as of right now im clueless.
http://www.jegs.com/cgi-bin/ncommerc...50&prmenbr=361
Thanks, Joe
http://www.jegs.com/cgi-bin/ncommerc...50&prmenbr=361
Thanks, Joe
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Yes it will work.
Keep in mind that a 400 is about 15% larger than a 350 (duh); so everything in the system — EVERYTHING — needs to flow 15% more at the same RPM. Or, turn that around backwards, and consider that if something maxes out at 6000 RPM on a 350, it will max out at around 5000 RPM on a 400. Think BIG.
Keep in mind that a 400 is about 15% larger than a 350 (duh); so everything in the system — EVERYTHING — needs to flow 15% more at the same RPM. Or, turn that around backwards, and consider that if something maxes out at 6000 RPM on a 350, it will max out at around 5000 RPM on a 400. Think BIG.
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Just a side-note - is your block a 4 or 2 bolt main? If you're going for real big hp numbers (over 550ish) and lots of RPM, you're safer with a 2 bolt with a good set of studs. Just a note.
Ty
Ty
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As far as I know all 400's were 2 bolt mains....
Oh and one other thing
Horsepower is what sells cars, TORQUE is what moves them.
Oh and one other thing
Horsepower is what sells cars, TORQUE is what moves them.
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Originally posted by 4BoltMain
As far as I know all 400's were 2 bolt mains....
Oh and one other thing
Horsepower is what sells cars, TORQUE is what moves them.
As far as I know all 400's were 2 bolt mains....
Oh and one other thing
Horsepower is what sells cars, TORQUE is what moves them.
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most 400's are 2 bolts cause the only 4 bolt ones were only made from 1970-73. From 1973-1980 they were 2 bolts. I have a whole casting number list here if you would like to know what yours is. I believe that most if not all of the 4 bolts had the casting number 3951511. hope this helps
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Car: '83 Z28, '07 Charger SRT8
Engine: 454ci, 6.1 Hemi
Transmission: TH350, A5
Axle/Gears: 2.73 posi, 3.06 posi
Originally posted by Parrydise7
Chevrolet introduced splayed four-bolt mains to correct the problem.
Chevrolet introduced splayed four-bolt mains to correct the problem.
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Car: 89rs (previous 2.8)
Engine: 406
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Thats right! I had a 327 one time that came with 4 bolt Mains..now we all know there are no 4-bolt 327's. Someone had enterd splayed caps along the way.
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Car: '83 Z28, '07 Charger SRT8
Engine: 454ci, 6.1 Hemi
Transmission: TH350, A5
Axle/Gears: 2.73 posi, 3.06 posi
Originally posted by Riley's35089rs+
Thats right! I had a 327 one time that came with 4 bolt Mains..now we all know there are no 4-bolt 327's. Someone had enterd splayed caps along the way.
Thats right! I had a 327 one time that came with 4 bolt Mains..now we all know there are no 4-bolt 327's. Someone had enterd splayed caps along the way.
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Originally posted by CaptPicardsZ28
Actually that is false. All 400's were not 2 bolt mains. The 4 bolt mains were weaker than the 2 bolt. Like everyone said, get the right combo of stuff and your good to go. You will be very happy with a 400. They are in high demand and getting harder to find. I had mine bored .030 over. My next one will be .060 over.
Actually that is false. All 400's were not 2 bolt mains. The 4 bolt mains were weaker than the 2 bolt. Like everyone said, get the right combo of stuff and your good to go. You will be very happy with a 400. They are in high demand and getting harder to find. I had mine bored .030 over. My next one will be .060 over.
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Car: 83Z28 HO
Engine: Magnacharged Dart Little M 408
Transmission: G Force 5 speed
Axle/Gears: Moser 9" w/Detroit Trutrac
And there's something wrong with a lot of torque?? I just don't see it myself. You want a strip only car, or a street/strip car?
Strip only, I'd build for HP in the upper rpm range. For a street/strip type build, I'd bring everything down to a more useable rpm for the street.
As mentioned above, it all depends on the combination of parts you put on it.
Oh BTW - If I were building a strip only car, I'd go with a 2 bolt, or better yet -splayed main caps. For a street engine, either a factory 2 bolt or 4 bolt should hold up to 6 grand I would think....
Just my .02
OOOHRAHHH!!!!
Strip only, I'd build for HP in the upper rpm range. For a street/strip type build, I'd bring everything down to a more useable rpm for the street.
As mentioned above, it all depends on the combination of parts you put on it.
Oh BTW - If I were building a strip only car, I'd go with a 2 bolt, or better yet -splayed main caps. For a street engine, either a factory 2 bolt or 4 bolt should hold up to 6 grand I would think....
Just my .02
OOOHRAHHH!!!!
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Car: 1987 Iroc-Z28
Engine: 350 TPI
Transmission: auto
Originally posted by five7kid
Start with a Motown shortblock, you've got the stuff capable of real power.
Start with a Motown shortblock, you've got the stuff capable of real power.
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