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400SB mod questions

rwright07

rwright07

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corporate hobo
hey im wondering wat you all think i oughta do

im a 16yr old w. a limited budget but im lookin to get more power n efficiancy outa my 400SB blazer

what would be a cheap and easy mod i could do by myself or with a little help from a mechanic that i know that loves to help me out

thanks,
rick
 
what have you done so far??

Intake and headers are the quickest bolt on deals. Don't have to pull the motor to do it. Fairly affordable.

Best thing is probably a tune up. New plugs and wires, cap and rotor, Air filter.
 
before you do anything make sure that thing isn't gonna get hot... I'd get a nice 3 core radiator and maybe a new fan, and a 160 thermostat before you do any mods to it. 400's are notorius for overheating due to poor head and block design.
 
Ok, you want power and efficiency so lets start with a full length hedders and a tuned exhaust using low restriction mufflers and 30" collectors.........
then upgrade the ignition system with a MSD 6AL super HEI kit.........
next on the list would be a very mild cam to increase the volumetric efficency of the engine.........
Installing a electric cooling fan will free up some hp and save fuel......
a low friction lubricating oil such as Amsoil will also add some ponies and mileage.......

start there and see how ya like it bro... :bow:
 
dirtwarrior17 said:
before you do anything make sure that thing isn't gonna get hot... I'd get a nice 3 core radiator and maybe a new fan, and a 160 thermostat before you do any mods to it. 400's are notorius for overheating due to poor head and block design.
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sorry i dont agree with some of this. i have a built 400 sbc with knife edge crank,polished and debured rods and crank , all balenced and flat tops. the whole nine yards . was from a 13's 1/4 mile car. put it in my 1 ton with 38 tires and it was 6500 lbs truck. i had 3 core with no shroud no clutch fan , full shroud no clutch fan, full shroud clutch fan . and all combos of this. it stayed 210 all the time no matter what it did for use.
 
bucksntrucks969 said:
what brand intake and headers should i run? amd how much would they cost me?
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You can try the regulars like summit or Jegs or something along those lines. Those are probably your best bet on a budget as you said. Neither of these is going to feel like a big kick in the pants for power but together they do help. Neither of these is going to help though if your current set up is in need of tuning. Can't stress that enough...
 
i have a 400sbc too... I am boring it .60 over.. THe water jackets are cemented.. Will this motor run extremely hot or what??? Just curious... I got 202 heads for mine that are gutted out... This motor was running low 12s in the 1/4 mile(@ .40 over).. time to put it in the K5..
 
210 degrees is too hot bro......the water temp needs to be kept down around 180 bro :bow:
 
i have a 400sbc too... I am boring it .60 over.. THe water jackets are cemented.. Will this motor run extremely hot or what??? Just curious... I got 202 heads for mine that are gutted out... This motor was running low 12s in the 1/4 mile(@ .40 over).. time to put it in the K5..
Click to expand...

you can't run that motor on the street, with the block filled with devcon there will be no water circulation thru the block or up to the heads.
That is a drag engine that makes a quick pass down the 1/4 mile and shut down to cool off for the next round. :crazy:
 
the blocks aren't filled all the way... Water still flows... Boring the motor 60 over makes the bottom walls weak so filler is put into the water jackets to make the bottom stronger..
 
Just as a suggestion, if it were my block and partially filled, i would want to run an oil cooler. I agree that you can run a partially filled block on the street, but it will slow down the transfer of heat out of the bottom end.
just my $.02
 
Does that plug up the steam hole? Usually not a good idea to plug the steam holes on a street bound 400....

How are you going to compensate for that? I am thinking those siamesed cylinders will get a bit to hot in the centers....

Hmmmm, the roundy round guys plug the deck of all this stuff, and things get pretty warm during a 30 lap feature, how do they keep from burning them up?
 
Going .060" over w/o sonic checking the block is asking for trouble....but then again 400 blocks are fairly old and were probably cast fairly thick :bow:
 
bucksntrucks969 said:
what brand intake and headers should i run? amd how much would they cost me?
Click to expand...

Get some Hooker headers and an Edelbrock intake. They are good quality brands.
 
Hooker's have smallish 2.5" collectors, get a pair of Hedman's instead with their 3" collectors and better fit/finish.
Performance Products makes a dual-plane intake identical to the Edelbrock unit that costs 40% less.
 
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