In 2001 I had my Impala at a local track along with my brother in law with his Mustang. We were with some friends who were also competing in the Show and Go that weekend at BIR. One of the guys we were with had a really "nice" King Cobra that had been set up as a track only car. He must have spent 10's of thousands getting this thing from a Stock POS to a decent drag car. He was tipping the scale at 375 to 400 and was about 5'8". Heart attack in can just waiting. Like most racers he wanted to go faster and couldn't for the life of him couldn't figure out how to lighten up the car anymore.
Well after we put the cars away we hit the beers and Capt Slug-O was on his like 6th six pack still trying to figure out how to make his car faster. His buddy leaned over and gave his huge beer gut a wack and told him to loose 200 lbs. Well the fat **** never thought about that. DUH!!! Or hire a midget to drive his car for him. I was LOLing as the rest of us were.
I am assuming the OP knows that already since his question was strickly about weight... and IMO, loosing 50 lbs is pretty good.
He wasn't asking about the performance gain of installing stock aluminum heads, he was looking for the weight difference. This isn't just another newbie asking "how much faster will I go with stock aluminum heads".
That is exactly what I am looking for. To me, at this point, 50 lbs from the nose of the car will help in lightening up and with the weight transfer when launching.
I pulled the car off the trailer and have retired it for this year. I feel the car has come along way this summer, after allot of trial and errors. I have acheived beyond my goal what I was looking at doing. My best time to date is an 11.59 with a sluggish 1.64 in the 60'.
Now it is time to start thinking about next year. What can be improved? For starts, putting the whale on a diet.
My cast iron heads have served me well. I ported and polished them myself and had 2.00" intakes and 1.55 exhaust valves dropped in. I also know they were very heavy. Well, the next step, knowing that there is a 50#s weight savings there, a set of GM aluminum heads with a little AI work done to them will help.
So,, my goal already, a set of aluminum heads, for the weight reduction, with of course some mods also, along with removal of the AC Delco battery and replaced with an Odyssey PC680, will save me approx. 65 - 70 pounds right off the bat.
Not a bad start in my books.
When swapping my LT1 powered Monte Carlo over to aluminum heads, i took the time to weigh them. Iron heads were 40 LBS each while the aluminum heads were 22 LBS. Each head had springs installed but no rockers. Not quite 50lbs but still a decent weight loss.
Most people on this forum know that iron heads will outflow their aluminum counterparts stock vs. stock. I was personally considering switching my wagon over to stock aluminum heads because...
0) They weigh less. Add this to my weight savings from the roll pan install, MH crossmember, 9.5" converter and some other misc items and I am creeping up on the weight of a stock SS!
1) I had a set of 374s laying around. Ended up trading them for impala door panels & carpet.
2) They already have screw in studs. I would be able to swap over a SMALL cam like a GM 845 or Crane 227 (if I could find one) and not need to modify the studs and springs. Small amount of $ savings, but still money in my pocket.
3) Iron heads have a larger chamber 64cc than the aluminum heads (either 58cc or 54cc depending on casting). The smaller chamber combined with a thinner head gasket would yeild a pretty good jump in compression, which never hurt anybody.
Iron heads are cool too though. Especially if you ported them like Willie did!