I have a decent stock rebuilt shortblock that I would like to install into my car. I'm just trying to get a nice upgrade over the 305 for now without spending a ton of money. I just need help deciding on heads.

The block is an 90-92 roller block (flat top pistons). I would like to run a pretty decent cam, along the lines of an xe276hr (224/230 .502/.510 110*), along with new springs/retainers/etc. I have both 081's and 083's at my house, but I have also seen a set of the 3973487 in my local junkyard, is it worth it to use these heads?

So far my searches on the 081/083 all show them as being a kind of low performance head, the 487's don't come up nearly as much in the searches but they all seem to indicate being pretty decent, but having a larger chamber than the first two heads, which is a bit of a problem since the 276 requires 9.0+. Any help you guys can give me is greatly appreciated.

Btw,

The car currently has an 84 LG4, holley carb, performer rpm intake, 1.5 roller rockers, 2200 stall, 3.73 gears, th350. It's a Monte Carlo too, so I hope you don't mind me stinking up your f-body fun with my brother's ugly car.

 

The larger chambers mean nothing, infact, a larger chamber brings down the compression ratio, potentially bringing down power.

That being said, if you want to run a forced induction system, the lower compression is needed.

The 081/083 heads, are actually fairly good flowing heads, that port out nicely.

if you are building a 350, id say do some pocket porting on the 083's, bowl blend them, clean them up, and they will treat you well.

 

I've never seen a ton of great comments regarding the 487 heads, so I probably wouldn't go to great lengths to get a set of them. Of course, if you have the cash, aftermarket heads are always the best way to go, which I'm sure you're already aware of. The 083's have the 64 cc chamber, which is ideal for most performance 350's, so I'd say just go to town porting a set of them and throw them on. Good choice of cam by the way. I've been eyeballing that exact same cam for my 350. IIRC, the 487's have a 76 cc chamber, which screams smog, low perfomance 70's head in my book.

 

The 083's will give just shy of 10:1 if you haven't decked the block. That's good for that cam.
The 081's will bump the CR up a bit more then that, unless you open up the chambers.

I'd zero deck the block, and port the snot out of the 083's, and use a .039" thick composite head gasket. 2200 RPM stall is barely above stock isn't it? I'd go larger if you can. The rest of the combo seems well matched, it should just ROAR.

 

Stock converters are like 1300-1400. At the time when we bought the converter, the car had 2.29 gears in it (ouch!). Before the gears, that converter was wayyyyy too much, now it's wayyyy too small.

Without decking the block, what gasket should I use with 083's ?

 

Use a straight edge to see if you need to deck the block before you decide if you are going to or not. If you need to, (.002" off flat), then zero deck it.

If it's DEAD-*** FLAT, then use a GM steel shim gasket. If it's inbetween, then you can use a composite, they're more forgiving, but you'll have a heinous quench, if you're using 1.54" compression distance pistons (like speed pro H345's). .025+.020+.039 = ugly!