A surprise under the hood... need some help plz.

[VWBeamer]

The seems Previous owner already fixed it for you with the new pistons and heads.

Originally Posted by 72TealnWhite

[ Reducing the Compression Ratio. This is what killed the muscle cars and the HP in our trucks.

Is there a quick fix for this?

Thanks for all the help

Still searching for the origin of the heads ..[/QUOTE]

[geezer#99]

FYI. Around 1972 the factory started rating their engines differently. The same motor that was previously rated at say 255 horses was the same motor at say 175 horses. Only diff was higher horsepower number was calculated without any accesories attached to the motor. Bare bones motor without any thing to drive like the altenator, power steering pump, the fan and on back to the convertor on the tranny.
Compression was dropped to 8.5 to one compared to some pre 1970 motors that had 9.5 to 11 to one compression.

[bruceman1968]

Originally Posted by 72TealnWhite

the guy told me it is positively bored .30 over. so does that mean cylinders and pistons .. im not sure...
nate

It means that the cylinder bore was 4.00in and it is now 4.030in so your pistons were 4.00 and the new ones are 4.030. When the bore gets bigger the piston must get bigger to Fill The Hole.

Originally Posted by 72TealnWhite

thanks, Is it really a must to know where the block came from, to configure the right parts.. It is good to know and can help alot. It seems like the PO or before just pieced this block together with parts from diff cars.. like someone told me the exh. manifolds were from a 71-74 corvette, and he mentioned other examples as well. is this not good? It's fine and common or is the chevy 350 a pretty compatible block with most anything from other vehicles? The gen1 small chevy is pretty compatiable with other gen1 small blocks . am i looking too hard into it.? no, it's good to have as much info as possible. i mean is it really not that important to know the roots of your engine? Roots are good to know.

thanks
nate

Originally Posted by 72TealnWhite

does boring it out pose a threat to the block itself? The short answer is NO. The more you bore the greater the chance of a problem. This is NOT anything for you to worry about, cause your motor has run fine since the overbore. .