Riley P

Staff member
Power User
Jan 11, 2009
2000 Z51
I was just reading an article on the LT1 for the C7 (anything to distract me from work).

Anyway, why is it whenever it's mentioned that the cam is in the block, they always have to mention that this is an outdated technology? Why are OHC engines regarded as the best engines out there? The article compared the new LT1 to BMW's 4.4 liter V8 and found that the LT1 is only 465 lb compared to the BMW's 503 lb engine. It's also 5 inches shorter in height and makes 50 more hp. So I guess I just don't know why the press has to bash the fact that it only has two valves per cylinder and that the cam is still in the block every single time they talk about the LT1.

My thought is that if OHC were the norm and someone stuffed the cam in the block, it would be regarded as great as it has less rotating mass, is lighter, more cost effective, etc.

The only advantage I can see an OHC configuration having is that you can adjust the intake valve timing independently of the exhaust cam. Maybe you can squeeze extra horses with this set up but I don't think the Corvette is hurting for more hp as much as it is for reduced weight and low engine height.

There are SOHC's and DOHC's which apparently are more efficient, lighter, have fewer moving parts (no rockers, pushrods, lifters) and thereby less ware and tare and heat generated. -- remember chevy's 1990 to 1995 LT5 engines?

Marvellous engine with great performance but expensive to build.

Chevy has eons of experience with the cam in block/pushrod engines and all but perfected them from it's humble beginnings in 1955 as a 265 cu. in. motor, apparently with excellent numbers with respect to performance and effeciency for pollution control.

It's probably that GM will eventually go to overhead cam engines but so far they've done so well with the traditional config. they've not had to do so.

I don't pay much heed to the press -- they're just digging for a story. I don't think they know much about engine diffs.

Right, right. I forgot about less moving parts. I was doing a quick read on the LT5. No mention of height increase but it is stated that it weighed about 40 lb more than the LT1. When every pound counts, I guess 40 lb is a lot! Especially on the front of the car.....but it did end up making 105 hp more than the LT1 and 75 more than the LT4 if I remember correctly... which makes those 40lb seem to melt away!
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