After looking around i think i have decided to put these onto my 1991 z28 with the 350 tpi but since i am new and when i went to jegs to look at them i am confused on what the difference between a 64cc chamber and a 70cc chamber yea i know its bigger but what does that mean and what would be better for my car granted that it is going to be used mostly for street use and tracks every now and again also what cam goes better done the search and everyone seems to have a different opinion i am trying to get all the parts matched up as best as possible and i know i am going to need some better runners and so on thanks for any replies

The size of the chamber will affect the compression ratio of the engine. The smaller the chamber the higher the compression ratio. There are other factors that determine compression ratio also. Has the deck height of the block been altered? What pistons are in the motor?

If everything is stock then I would get the 64cc chambered heads. It will bring the compression ratio to around 10.5:1.

I used to run the RPM combination, heads, intake, camshaft but with a carb. I ran mid 12's in the 1/4 mile and could still use it as a daily driver. These parts are matched perfectly.

I'm using the same RPM heads on my current combination and I'm running in the 11's.

Head gasket thickness will also play a factor in compression, but more importantly, quench.

The performer rpm heads are sound, and will make good power. But they have really small intake runners and not very good flow numbers. I know that despite this they are a good design, but I think a set of vortecs would be money well spent, they flow very similar, are cheap, and always make good power.
If I wanted to buy a new set of aluminum heads, I would contact competition products. They still have a larger stock of pro topline aluminum heads, which are identical to rhs, for a really discounted rate. Otherwise, I would say afr is the way to go.

with all that said anybody now how much better the afr's are over the edelbrock and what would be good for a stock l98 the 180cc/65cc because at the place mentioned above there are only a little more then the edelbrocks and any other light on the situation would be apperciated i am new at this a would like to start in the right direction thanks.

Comparing AFRs and Edelbrocks is like comparing night and day.

That's the biggest problem with Edelbrock heads. It's not that they're bad, just that if you're going to spend all that money on aluminum heads anyway, there's so much better available for just a little more money.

The AFR Eliminator 195's, w/62cc chambers, are working great on top of my stock L98 short-block. See sig / PM me for further details.

Bill

P.S.: I think I saw you / your car at the Rancho Vista Von's market a couple weeks back...

I am sorry, I do not completely understand your post, what do you mean by "the place mentioned above"? and"there are only a little more than edelbrocks"?If you are comparing the price of afr to edelbrock then you are correct, AFRs are money well spent compared to Edelbrock.
If you are on a budget, stock vortecs are cheap and will work well, and pro-toplines are really cheap now, they are selling out there existing stock, so if they have what you need, a 180 or 200 cc runner, the price will be right.

there should have been a linked posted to a site that had a pair of the afrs that where i think around 1400 for both mabey a little more

search about pro-topline's before buying as there are a lot of horror stories about them. Seems like older ones are ok, but newer ones are not very good

When it comes to choosing a cam don't take anyones word for it. No offense to anybody here but I personally believe that your best bet would be to decide what brand cam you want, I'd suggest COMP, and then just call thier tech line which will be listed on their web site. It won't cost a thing for thier advise. You can discuss cams with them, they are gonna want some basic info on your car like, vehicle weight, final rear gear ratio, type of trans and stall, specs on your heads, engine displacement, compression ratio. Have that info ready when you call. Then they'll want to know what your trying to achieve from your car. This whole thing takes about thirty minutes. Once they know exactly what your wanting from your car then they can suggest what cam in their cataloge would be best or even suggest a custom grind for you. It's the only way for YOU to be sure you are getting the right cam for the power and "personality" that you want from your engine.
I did this through COMP, and I ended up getting my entire valve train from them including a custom grind and roller rockers for under 500 bucks. You don't have to use COMP of course, I'm sure the other cam manufacturers would do the same thing.

Cam help is a free service, and one that a novice builder should absolutely use. But I feel you would be better off getting advice from a local engine builder with a good reputation. My reason for this is because I have called cam help (comp cams) many times, and you do not ALWAYS get an expert, I have talked to a few knowlegable techs, and some guys who really do not know a whole lot.
Case in point, I called for some basic info betwwen two cams, a 290 extreme energy and a 292 magnum. Well. rather than get a straight answer, I got a cam reccomendation for a comp 268 magnum.
Now dont get me wrong, I am sure it is a fine cam, however, I have a 11.5 compression 383 with a single plane intake, full length 1 3/4 headers, 4000 stall and 4.10 gears. It runs on race gas and is only driven for short trips around town. The tech knew this info and still suggested that small cam. I am sure he meant well, but what was he thinking?
I am sure they will give you good advice, but they are always a liitle conservative in my book. Now I am not suggesting you buy a big cam, but rather, talk to an experienced engine builder in your local area that has a good reputation, he will point you in the right direction on not just the cam, but all the other little details someone can forget.

cam techs always suggest a smaller cam for liability reasons.

i had the edelbrock performer rpm heads on my motor in my s10 blazer.
the motor cam out of a 91 Z used the stock bottom endm those heads, an lt4hotcam from an lt1 ( it was sittin on the shelf and better then puttin a stocker in there ) a rpm air gap intake, a holley 670 carn. im my blazer through a 700r4 w/a 2400 stall it put down 330 rwhp 345 rwtq.
so the heads are pretty good even with small cams.

The Performer RPM heads are good, and less expensive than AFR's. I use them on my HSR setup along with the Performer RPM roller cam. The lifters and push rods are Comp Cams..The RPM heads do not have heat cross over and use the 86 earlier intake. I was skepitcal at first of the cam, due to I have always used Comp products..But it has a very good sound, seems to be very peppy..