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how to muscle up a 400 sbc

  
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how to muscle up a 400 sbc

 
ecb_camaro ecb_camaro
New User | Posts: 1 | Joined: 10/09
Posted: 10/29/09
07:17 PM

Just bought a 400 sbc with 90,000 miles on it for my 86 camaro. the engine came out of a 91 pick up. Before I install the engine, what can i do to increase the performance of the engine?  

gtomustang gtomustang
Enthusiast | Posts: 457 | Joined: 06/09
Posted: 10/30/09
11:25 AM

Its a basic small block, except that any cylinder head needs to have steam holes drilled into it (get 400cid head gaskets, to use as a template) and the connecting rods are shorter (5.56 versus 5.57 inches).  

Pick a cylinder head, a cam to match it, and an intake and exhaust header package legal for your state.  
Just because you can't do it...doesn't mean its impossible

bdvdw bdvdw
New User | Posts: 34 | Joined: 12/08
Posted: 10/31/09
05:42 AM

5.565rods (factory sbc400) vs 5.7 rods any other second/3rd gen sbc  

gtomustang gtomustang
Enthusiast | Posts: 457 | Joined: 06/09
Posted: 10/31/09
02:03 PM

now that I'm not typing the answer at work.... Laugh
Find out what exhaust is legal for your car.  That will be the breathing restriction on an engine 50cid larger than anything planned for this car by Detroit.  Cam it, and "head it" according to what the exhaust will flow out of the engine.  then gear the rear axle according to what cam you are running.  Engine tech in 1986 was to make torque from idle to, say, 4500RPM.  So, you may find sticking with "highway gears" and designing that 400cid to work within this RPM spread, to be the ticket.

Edelbrock, and others, offer head/cam/intake packages designed to work together. Or just pick one part you like, and ask their tech line what else goes along with it. Check into GM's optional 1LE brake packages, or Baer or whatever fits your budget. Z28s did come w/ a cowl induction package, or design your own.

your generation of Camaro was the first to be designed from the beginning to be a Z28 suspension, while others prior were designed for the 6 cylinder first, then attempted to make handle.  So, you shouldn't need a whole lot to get this car to handle the power you can make...and there's plenty of companies willing to help you go wherever you want to go with this car.  
Just because you can't do it...doesn't mean its impossible

Sarg Sarg
New User | Posts: 2 | Joined: 12/09
Posted: 12/07/09
11:21 AM

It depends on how much you want. The 400 is different than other small blocks. Heads have steam holes between the inner cyls. and the rods are short. Is it a 2 or 4 bolt main? and how much do you want to spend?. I guess most all the small block heads can have the steam ports drilled in them and remember to get the right head gaskets because only the 400's have the steam ports drilled in them.
Most all 400 heads are 76cc some have big valves 1.937 and 1.6 and they have little sharp camel humps for identification at least mine did. 2.02 and 1.6 with
A nice 3 or 5 angle valve job is always nice. If you use other heads they must be drilled or you will never keep head gaskets in it.

Personally the longer the connecting rod the better, but you have to have the pistons to match the rod length. Check the rotating assembly very closely to make sure it all clears the bottom of the block. The 400 was externally balanced vs. the rest of the small blocks, so make sure you have the right flywheel auto or manual. Most the early 400's only came with a 2 barrel carb. Personally I prefer a single plane intake manifold with a 750 cfm carb,4 tube headers are nice too. Whatever you decide I wouldn't go beyond 10 to 1 on the compression for the street. Another thing to keep in mind is cam lift vs. duration. I like to use no more than .550 lift with about 300 deg. duration with 1.6 rockers. This gives you mid range to high end and will keep it streetable.
It is advisable not to bore the engine any more than necessary because if you have any problems like broken rings and pistons you will be able to bore it again if your lucky. The engine barks loudly and will pull 6000 with power.
Just my opinion I am sure there are many more and probably better stated.

Sadeek  

Sarg Sarg
New User | Posts: 2 | Joined: 12/09
Posted: 12/07/09
11:24 AM

see Sarg below  

happygrouch happygrouch
New User | Posts: 1 | Joined: 01/10
Posted: 02/01/10
02:54 PM

I built a 400 that had Bow-Tie Angle plug heads (with steam holes). I had a guy in Atlanta grind a cam that turned out to be outstanding. The motor went into a 78 Nova that weighed a ton. It pulled that car along like you would on believe. I tried several carb and manifold combination to feed it and the cam just kept giving power. The car didn't have a stall in it and I wanted to have some vacuum for the brakes. I ended up using Edelbrok TORKER II. I did try the Victor and a Bow-tie but they were just to much without changing a lot of other things on the car.

Here are the specs - http://bit.ly/cU8CBK - I plan to write a story about the car so if the link changes do a search on the site for 400_cam.jeg.


If you would like more details let me know...  

bdvdw bdvdw
New User | Posts: 34 | Joined: 12/08
Posted: 02/01/10
03:13 PM

yep 400's make alot of power. but if they were durable g.m. would still make them.

i used a 224/234 duration at .050" lift
.442/.452 lift. cheap $80 summit racing cam and lifter set, hpome ported 86 305 heads off a tuned port motor. 18cc dish pistons and 5.7" rods. with the tpi unit it pulled like gange busters.
but i did have it in the garage for a long time trying to figure out how to keep it from over heating. a factory single electric fan won't do it. look for the dual electric fan set up off an 88-92 car. another tip, use a fan shroud........
the factory dual fans, and factory radiator work good.

but aftermarket dual electric fans with no fan shroud don't work.  

gtomustang gtomustang
Enthusiast | Posts: 457 | Joined: 06/09
Posted: 02/02/10
01:10 PM

Actually, Chevy got rid of them when gas prices were going up in early eighties.  A big v8 wasn't welcome, and the real small ones--the 267cid, 292, etc--were real weak jobs, with thin webs and little nickel in the cast.

How did those peanut port 305 heads work after 5000RPM? I remember that used to be the deal for small chamber heads, but the ports....and yeah, those F-bodies didn't have much grill to feed the radiator cold enough air...  
Just because you can't do it...doesn't mean its impossible