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400ci rebuild questions

orangeGMC

orangeGMC

1/2 ton status
Joined
Dec 26, 2004
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Location
Connecticut
I have a freshly rebuilt 400 short block, that I got for free. I am thinking of putting Vortec heads and vortec style manifold on it. I am not trying to build a high horsepower motor, but would like more torque than the tired 305 I have now. I am trying to keep costs low and don't want to use aluminum heads. I like the fact that the heads come preassembled. I know I will have to drill the steam holes, Does any any body have a procedure for that?
 
Yea, get a 400 head gasket......x marks the spot.

I wish you wouldn't put Vortecs on a 400.....jeez louise
 
Well I just got the original heads that were rebuilt with the motor. I don't have any specs on them yet as they are still at my buddies house. Can I make decent power with those? Cam and lifters? Intake? Rockers?
 
Just use the heads that came of the motor as the steam holes are already drilled.
The Comp XE268H will really wake that motor up and is compatible with the stock springs (I think), Intake manifold should be a dual-plane (not a high-rise) with your choice of carb. (650 cfm max)
Roller rockers (stock ratio) are a great investment on any motor as they decrease friction in the valvetrain and promote longer valve-guide/seal life because the rocker rolls across the top of the stem while opening the valve instead of dragging/sliding across the stem and forcing the valve sideways in the guide while opening the valve.
Roller rockers are worth 15-30 HP and increased torque as well depending on application.
Make every effort to keep that motor cool up to and including a high-flow water pump, 160 degree thermostat, "Redline water-wetter" additive, conservative ignition timing, use the factory fan-shroud make sure the fan-clutch is working properly.
keep that 400 cool and it will provide many years of good service :bow:
 
If you don't have the stock heads...I have the ones off my old 400. They are in great shape and only have 10,000 miles on them, let me know.
 
In keeping with my "practice what i preach" sentiment.....
The 400 has a lowwwwww rod ratio of 1.48:1 and would not be happy with the 268 cam, go with 1 of the XE 4x4 cams that Comp makes and match the powerband with the rpm range of a 400 SBC which is idle to around 4500 rpm.
The smallest of the bunch would probably be a great choice.
 
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