Heres the scoop, my car needs new valve springs and valve seals. The heads currently have press in rocker studs. They are 76cc chambers, and the car has flat top pistons. The motor is pretty much a stock 350 4 bbl out of a 1971 blazer with a cam in it. The cam specs are .462/.469 lift, 218/224 duration @ .050. Its an extreme energy grind. My logic is why put money into old heads when I can just get new ones instead of having to upgrade later on. The motor currently is kept lower rpm, and has a computer controlled carb. When this current motor blows, its getting built as a forged 383 to take boost from a blower. But until then, Id like a performance gain on the 350. The motor has 100,000 on it and a new crank was just put in.

My dillemma, should I get new heads and which should I get. I was looking at the 180 cc pro action lightning, and these posted awesome numbers in desk top dyno for me. 397 hp. I also tried the sportsman 2 heads, and got something like 370. Currently, it says I have 305. I just worry about putting too big of heads on the motor. Will be kept to 6200 and below. Manifold upgrade will happen. Im looking at putting 2.02/1.60 valves in it, but I worry about compression. I have no problem dumping in 94 octane in the car, and my compression would be in the low 10's with 64cc chambers, which I think is the limit.

What heads should I get for this motor, even if i didnt mention one. I am open to suggestions all over. What size valves should I keep it at? Combustion chamber size? things to watch out for? I want to maximize my street power from 6200-below, and I was planning on later a higher stall converter and a slightly larger cam, but I am really worried about losing performance (ala danger mouse in super chevy when it got torquers) and this is a huge amount of money for a poor college student to spend, so I want to get it right the first time.

Thanks a lot, and sorry for the long post, this is my biggest car decision yet, as for what heads I need.

I just ordered the aluminum Pro Lightnings for $870 shipped.

if you're interested in them, they were on sale, and at $1000 now, but I talked to the guy and a group purchase of 3 at least he'll knock it back down to the sale price.

For a truck like your Blazer, or even a street driven fbody low rpm torque and throttle response
is paramont. You would want to select a head that has small high volocity ports, yet enough flow to make power too.

A 64cc chamber, 170cc port, high flow head fits the bill.

One tried and true winner are Vortec heads. They will get
you the power and torque your looking for and the $price$ is hard to beat.

You can buy a good dual plane vortec manifold for less than you think from Professional Products.
www.professional-products.com
The vortecs will need a few mods before you bolt them on but will deliver the goods..... These heads have room to grow too
in the future. This will get your the most bang for the buck in a new head.

Go to http://www.chevyhiperformance.com/

Find the search button and click on it. search for vortec.
There is a ton of info on vortec headed buildups there for ya
from past articles. all the info is there.
You won't be dissapointed with these heads.

I was thinking vortecs myself, but they arent a direct bolt in, and by looking at a roots blower down the road, Id need to get new heads, which Im trying to avoid again. The blower is at least 3 or 4 years away, but even still. The motor is in my trans am right now. The blazer is blessed with a bone stock LG4 now.

For a supercharged street motor you want a
low compression ratio. Just like you have now.
Your 487 casting heads would work well for this with some upgrades. install 2.02 x1.60 valves, new springs, screwin studs and guide plates or just pin the studs, them give them a max port job.

These 76 cc heads have as much flow potential as my infamous
ported 305 heads. With that kind of flow and a blower,
you be screamin' down the road.
Here is another option. Since you already have the right budget
blower 76cc head for the future, why not replace them with some hi compression $budget$ home/ported 305 heads in the mean time.
You'll get the cr and flow (power) you want now for low $$$'s
And you can get to work on those 487's for your Blower project.
The money you save will get you that much closer to getting that blower.

If the stock valves in your 487's are usable, throw them in a set of home/ported 416's.

Note 416's will be right about 60/61 cc's once you install the bigger valves. Just right.

I's not a Blazer any more.... that's just what the sticker said on the sheet metal that originally wrapped his cast iron

64cc heads on a flat-top 350 will give you about 10¼:1 CR. That's about the value to shoot for with iron heads.

Both suggestions should work fine; either will easily put you in the low 13s or 12s. Watch out with the Vortecs though: they come out of the box set up as truck service parts, not high-performance parts. There's more to making a set of high-perf heads than just their raw flow #s. They come with crap replacement 1.25" diameter truck valve springs, the stupid factory rotator mechanism and all that, pull-out studs, and guides that are so tall that the retainers smash into them at about .480" lift. Basically, by the time you get through overcoming all their shortcomings, you have almost as much $$$$ in them as you would in a set of entry-level true performance heads.

With the right heads, your cam should be OK. Add 1.6 roller rockers to get some more flow.

I have a set of 350 heads here I could play around with. My logic with doing the old heads over was it would cost just as much to get new heads, and it would be a better investment. the high compression is for off the blower, and it forces me to rebuild later for a blower. Otherwise, I will end up grenading the 100K pistons and rods in the motor. That and I plan on stroking the motor when rebuilt with 8.5:1 compression.

As of right now, Im looking for a nice street 350, something that will run mid 13's or better with sticky tires. Gas mileage is no real concern. I plan on keeping my CCC.

As for 305 heads, with 58 cc chambers, wont I get like 11.5:1 or some obscenely high compression ratio?

1. You can rebuild and rework your stock 76 heads for less than a set of new ones. Way less.

2. The ported 305 head will get you what you want for now.
And for less$$$.

3. No, your new cr will be 10:1 with 305 heads.

the 487's are one of the best of the open chamber 76 cc heads
and will port up nicely, for less$$$.
So you have some/ all of the right stuff already.
When you get yhe blower you could move the ported 305 heads to your truck. That 'ill wake that thing up

I'ts all up to you and your wallet. If ya blow a $wad$ on new 64 cc heads you'll be that much farther from that blower.
The ported 487's under a blower will make at least 550+ hp on the street.
thats a lot...

Just some ideas.....

I think Im going to get new heads for the car. I dont want to deal with a lot of machine work, and Im looking at a direct bolt on. As for putting the blower off, the car for now needs to pass emmisions, and I'd like to rebuild the motor before it gets blown, in which case the high compression problem would be nullified. If I do the blower, I want to do it right. Forged internals and stroked.

As for heads, is it wise to get 170, 180 or 200 cc runners? The 180 pro lightnings flow better than the sportsmans, and the smallish runners seem ideal for a street motor. By buying new heads, I will get better flow and more compression with less aggravation. I am not ready yet to attempt machine work. On the other hand when those 487's get pulled off, I may attempt to work them over anyways. The 487's could go on our 69 vette, which desperately needs a shot in the arm (currently peanut cammed 1972 2 barrel motor with a 4 barrel on top.) Id rather put good heads on the vette than the blazer. The blazer is a plow truck, and thats all it does.

Current plans are to buy the pro lightnings, 64 cc chambers, angle plug heads, 180 cc runners, 2.02/1.60 valves. I just hope I make the right choice. I keep going between new heads, the blower (if it makes 550 with 487's, it must make more with the lightnings), or porting the snot out of my 402's heads and throwing a big block in. Any money spent on the 350 isnt wasted, as the vette can take any parts that go on the bird. If I had it my way, Id just build the vette and drive the bird, but my mother thinks otherwise.