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292 inline questions

2K views 4 replies 5 participants last post by  CNC-Dude 
#1 ·
new to the website.

ok im building a 63 c10. i am planning on using a 74 292. and putting on a fresh 65ish head.

from what i hear, after 72 they were de-tuned for emissions? is there anything else different about this engine from an earlier model? aslo will it bolt up?

thanks
 
#3 ·
Emissions tuning is largley a reduction in cam timing, compression, and ignition timing. but since these engines went into trucks, they were already pretty detuned before the advent of emissions as the factory was configuring them to emphsize torque so they always came with a short cam having minimal overlap with an early closing intake to improve low RPM cylinder pressure. Compression was kept low so they would run well on regular grade leaded fuel. These are also the same tricks used on all engines of this period to reduce emissions.

If you looking to improve power (the 292 will deliver when set up for that goal) I'd recommend you get a hold of Leo Santucci's book "Chevrolet Inline Six-Cylinder Power Manual". It's a thorough read on the subject.

And yes to second BOBCRMAN's comments; the 65 head will need exhaust side hard seat inserts to live with unleaded fuel.

Bogie
 
#4 ·
There is a difference in the motor mount locations between the 230/250 and the 292 you may want to check that out.According to some of the older Motors Manuals they show the 1967-68 passenger car 250 producing the most horse power,some guys will seek the 194 head with its smaller chambers to boost compression and install larger valves. Before you jump into this project buy this:
 
#5 · (Edited)
some guys will seek the 194 head with its smaller chambers to boost compression and install larger valves.
Its been known for decades by top Chevy 6 cylinder experts including the late Kay Sissell that the 194 head is a bad choice to swap onto any engine except the 194. Kay even stated in his catalog and numerous Hot Rod magazine articles he wrote personally that "the 194 head head should never be placed onto any engine except the 194, for reasons of severe shrouding that cannot be corrected, even with extensive porting and unshrouding efforts."
These claims have also been proven recently on Inliners, where extensive dyno testing with both a 292 and 250 have shown repeatedly, that when a 194 head was swapped for a large chamber head prepped with the same valve size and lump porting mods, the 194 head engine made a minimum of 10 HP less throughout the entire RPM range every time it was compared to the large chamber head. This is a prime example of an "urban legend" and thinking that more compression = more power, and it just isn't always the case.
 
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