Ryan77

Does anyone have the valve sizes, flow numbers, etc for factory 882 heads for a '77 or know where I can find them? Thanks in advance :cheers:

greatgonzoglenn

A friend of mine had told me a long time ago (he raced circle track) that 882 heads were best used for boat anchors. Just my .02, I'm sure you could find better heads a resonable prices. Just a suggestion, but I've heard nothing but good about the Vortech heads, and are pretty cheap. :flag

PatsLs1vette

:iagree: http://www.prestage.com/dyno2000/Heads/SBC/GM882.flw


[Modified by patsnitrovette, 4:08 PM 3/18/2003]

Aaron-74

I've got my stock 882 heads on my Vette. I've got about 350.00$ and about 20hours of work into them. They've got 1.94 intake valves. The stock exhaust valve is 1.50 but I had mine punched out to 1.60 vavles. With manley SS polished valves. They're bowl ported on both the intake and exhaust ports. The exhaust ports have been elargened a little bit. I aslo had thick wall bronze valves guides installed. I had the spring seats cuts for the comp cams 1.450 single springs. And they've been decked to about 74cc in the chambers. They're decent heads. for under 400.00$ I'm not complaining. Machine work was 220.00# the valves were 113.00$. And we ported them at home. I didn't flow bench them after we ported them, but I've got the stock flow numbers somewhere. Here are some pics.






I don't think they're bad heads for whats in them. I've had some offers for them for 400.00$. But most people want the 64cc heads. Like I said, they're not all that bad. But there is way better heads out there. I'd really like to have some Dart Iron Eagles or maybe some old cammel hump heads. Anyways, hope this gives you a little help. I'm running a pretty mild motor, so I don't really see the point to super high flow big port heads yet..

Take care,
Aaron. :chevy

Aaron-74

The one thing I ldon't like about the vortech heads is that after you spend 5-600.00$ on the heads and machine work for bigger springs, you have to spend another 200.00$ or so for the intake and gaskets. Then you've got 6-750.00$ in heads. For another 300.00$ you could get some iron eagles or trick flows...just my .02$

Aaron

fauxrs

882 heads get a bad rap, and for some reasons rightfully so, they actually flow pretty well for what is otherwise considered a smog head. however flow flattens out from .400 inches on.

Up to this point the 882's flow as good or better than

>L98 aluminum heads (actually flow better to .60")
>GM 441 iron heads (actually flow better to .60")
>gm 462 iron heads (to .400")
They flow within a few percentage points of the LT1 372 castings
They are the near equal to World product SR torquers (to .400" lift)

So in a low-mid performance motor they are more than fine, however they are a lightweight casting meaning they are prone to cracking, and they do not respond very well to larger valves.

chamber size: 76cc
intake runner: 151 cc

0.100 (I/E) 70/58 - 82%
0.200 125/108 - 86%
0.300 175/135 - 77%
0.400 204/141 - 69%
0.500 205/142 - 69%
0.600 206/142 - 69%

many experts claim that the relationship between the intake and exhaust flow should be that the exhaust should flow @ 70% the intake flow - I added the percentage for reference.


These flow numbers come from Car Craft - Jan 2001

http://purplesagetradingpost.com/sum...fo/heads1.html


[Modified by fauxrs, 1:25 PM 3/18/2003]

Ryan77

Thanks for all the replies :yesnod: . I'm not looking for big power out of these heads or this motor because I'll be starting the buildup of my big block this summer. I'm just looking for some more power until the big block swap is complete, and head work on the 882's should run me around $600 for what I want done (I'll do everything except the machine work myself). I know they are the weak link in the package I have for now (see my sig). Thanks again :cheers:

Aaron-74

The XE268 isn't all that big of a cam. A decent ported 882 head will do all right on top of that cam. Just my opinion though. I'd spend my money on the BB....oh well. Good luck.

Ryan77

Aaron--It'll be awhile before the big block is complete, I'll be in college next year and the year after, so I'll be piecing it together as money allows
:crazy:

I still have a few questions though. What would be the best valve combo for my setup? 1.94/1.60 or 2.02/1.60? What cc would I have to shave the combustion chambers to to get 9.5:1 compression with the stock pistons? Will 9.5:1 be ok with 93 octane? Thanks for the help, I'm not familiar with iron heads, only aluminum :cheers:



[Modified by Ryan77, 7:29 PM 3/18/2003]

Aaron-74

I don't think you'll be able to safely deck enough off the bottom of the heads to be able to raise your compression enough to reach that point. Well, that depends on the stock compression. If it was around 9.0:1 then yeah, it might be possible.
I went with the 1.94/1.60 because I planned to one day run N20. But, that kinda went sour. My friend Jeff (no-radio) has 882 heads with 2.02/1.60 valves with an XE-268 and is pretty pleased. But, he's upgrading to AFR 190 heads now. 9.5:1 would probably be okay with premium gas. I had my heads decked from 76 to 74cc. I could probably take it down to 72cc or so, but the deck would be getting pretty thin by then and i would probaby avoid that since it would be easier to crack.

Anyway, good luck.

Aaron

Ryan77

Thanks, I'll probably go to 74cc and use a thinner head gasket then. Like I said I'm not going for huge power, just something for the time being. What would be the benefits/disadvantages of the 2.02 vs. 1.94 intake valve and vice versa? Thanks again :cheers:

Aaron-74

The 2.02/1.60 valves might make you lose a little low end (less velocity). The upside, the high end power might be raised a little. But, they aslo might make the chambers a little shrouded around the outside of the chamber. Making you lose a little power.

The red area about the intake valve and the chamber wall. That area is minimized restricing the air's spiral and how easily it's moved around the valve resulting in slowing and possible tumble in the air and causing a loss in power.

NHvette

I was reading on a past post that a cheap way to liven up the ol' L48 was
to work a pair of 305 heads (don't know casting #). The combustion chamber
is smaller - and compression goes from 8.5 to 9.5+ . That right there should
be felt in the seat of the pants.
:seeya

Aaron-74

I wouldn't go that route. 305 heads won't flow nearly as well. It'd be better to get high compression pistons and have a little work done to the stock heads.

I had a friend who did that to his Nova and yeah the lowend was insane, but after 4500 rpm it was a dog (XE-268 cam). He was so pissed he pulled the heads back off that day. :boxing


[Modified by Aaron-74, 7:06 PM 3/18/2003]

Ryan77

I was looking in to some Dart Iron Eagles on ebay, they are about the same price as the headwork I was looking to have done :cheers:

Aaron-74

:yesnod: Dart Iron Eagles are some of the best iron heads right out of the box. My Auto Shop teacher (In the NHRA Pro-Gas w/ 8sec Nova) said that the Dart Iron Eagles are probably some of the best iron heads around and with a few hours of port work with someone who knows what they're doing and a flow bench, then they'll out perform some of the higher dollar aluminum heads.

I'm saving for a set of Dart Iron Eagles.
With a few hours of port work, the 2.05/1.60 vavle set up, and a good polishing of the combustion chambers and exhaut ports those heads will really wake a motor w/ the right compression and cam choice.

I do remember a while back someone with Dart heads was having a problem with the mounting of the alternator or something. So, you might want to ask around about some of the problems people have had with mounting certain things on them..

-Aaron.

TedH

That was probably me on the alternator mounting issue. I think it was that I had the alternator bracket upside down or something. Everything went together great once I figured that out.

The DARTS, combined with headers, duals and all of the other stuff have really expanded the power band on my 350.

Aaron-74

i remember reading about that issue. I didn't remember who it was though.... ;)

Jvette73

I dont have flow numbers but I can take a good guess at combustion chamber volume and valve size. CC volume 76cc. Valves, 1.94 intake, 1.50 exhaust.


[Modified by Jvette73, 3:18 PM 3/19/2003]