Aluminum Block V8 engines- weight savings?

[preventec47]

30 years ago I raced in the SCCA smaller lighter and seemingly more nimble
vehicles with small 4 cylinder engines. As I grew up in the muscle car era I
remembered all those heavy cars with heavier motors were only good for
straight line performance and many trucks outperformed them in corners.

I have finally grown up and am ready for a V8 in something but I still
remember how important light weight is. From what I gather ( but nowhere can I find accurate weight figures) an aluminum block engine must be lighter than an iron block motor... but how much lighter ? Apparently the
General Motors LS series motors going back 20 years or more now mostly
have aluminum blocks and the LS engine folks all claim much weight saved.
There is a great summary article on this website about LS engines.
http://www.kitcarusa.com/kb.php?aid=57

So who has accurate info on the weights? Surprisingly the manufacturers and marketers of these engines do not know the weights. How can that be ?

If I was in the engine, kitcar, or auto parts business I would weight every
component part and provide spreadsheets with the accurate info.

The PROBLEM. Suppose I want to save weight with a Cobra kit car that usually takes Ford drivetrain parts.

Before we commit energy to the pursuit... we still have to know if it is
worth it... you know.... cost/benefit etc. If I incur great extra cost in
time, money and aggravation in trying to make it work.... it will not be
worth it if only 5 pounds are saved.

Not only that... but it seems to me that small block LS Aluminum engines
may put out as much power as older (much heavier-obviously ) iron big block engines.

I hope I am not treading on sacred ground here as I know other old timers who revere their "big-iron" engines like pets and I do agree there is some glory in the older behemoth V8 beasts..... Its just ... I like twisty roads too much.

I know that the proper european sportscar evolution resulted in the attitude of those "fat american fools" and their disregard for weight because of
their cheap gas- at least 30 or 40 years ago... in the recent decade or two - not so much. Just thinking out loud.... look at the contrast in weight between a Cobra 427
and a Lotus Super 7 with forced induction I-4 or V6

[Lucky@LeMans]

The LS series of engines are great and they are light for their size and capacity. The LS7 is probably the best for big capacity in a small package with most power for your £. Look at the Monster Miata set up's, big V8's in the MX5 chassis. Many are Ford V8's but some feature the Chevy LS motors. Most of these modern V8's will fit into your typical Cobra or similar style kit. Go for it !

[molleur]

A dressed LS engine is approximately 425 pounds.

[preventec47]

Originally Posted by molleur

A dressed LS engine is approximately 425 pounds.

Is that 425 for a small block or big block and how much less than the comparable iron small block or iron big block ?

according to my referenced article in the first post, it appears that there may be more
than a dozen types and sub types such as LS1, LS2 thru now LS9 I think.

It would be great to have a spreadsheet listing all the pertinent info for all the various
GM LS motors and for that matter all the other newer and older models from different
manufacturers. Why not include the six cylinders as well since so many cars are now
having their V8s replaced with V6s

[molleur]

Do a google search for engine weights and you'll find them.