Grinchia

I posted a while back about my mongrel engine, my quest for 500hp, and a broken valve I had to tear some stuff down to get to and fix. At the time I posted my head casting numbers for advice on what I got and what I might hope to gain by upgrading. Nobody came up with a firm ID on the heads, which are iron, casting number 3909802. I just found 'em mentioned here, 13th down the list:
http://www.prestage.com/Tech+Info/Ca...mbers/319.aspx

My intake is a tall dual plane aluminum unit with LARGE rectagle ports, makes the head ports look tiny. For those of you not recalling the rest of the setup, I have a 427 bored to 439, headers with sidepipes, some flavor of TRW pistons with compression running at either 10.5:1 or 11.25:1 (depending on who I believe...engine's history is a bit convoluted). I'm running a small-by-Lars-standards holley 670 street avenger carb (probably will upsize next year).

I'm rebuilding this winter, and strongly considering aluminum heads. Looking at the mismatch between my intake and heads, I'd have to do some MAJOR porting to get 'em to match up, and honestly unless these heads have decent flow potential, I don't think it's worth it. I really don't want to spend $2000 for aluminum heads though...I have a line on a fairly awesome engine I could get for $3000-$4000 that would make a lot more sense.

Can anyone tell me more about these heads?

Can anyone suggest a specific Aluminum head to consider if I do go that route? Does anyone have any cheap Big Block aluminum heads l;aying around?


:jester


-Roy

69ttop502

Roy, there are so many great choices out there now in aluminum heads. I went through this myself before deciding to go with a pair of CNC ported AFR 315's on my 502. The problem with almost all of the aftermarket aluminum heads is they have raised exhaust ports, anywhere from .3 to .6 inches. In my case I had to do some major tweaking to get my sidemounts to fit. If you are running manifolds it wouldn't be as big a problem but you would be negating some of the gains from the heads.
The GM and Edelbrocks which are the same head have the exhaust port in the stock port location so either of them would be a bolt in. In your case I would not rule out an oval port head as well although you would also need an intake. The other concern would be compression. I don't know about your pistons but if they are of closed chamber variety the new heads are all around 118 in the chambers so you might have to mill to get acceptable compression. If you go to Chevy High Performances website, they did an extensive test on BBC cylinder heads, some great info there. I am not sure on prices but my AFR's were 3000 bucks but will be all the head I will ever need. Good luck and fire away if I can help further.


Bill.

Brettmc

The chevy hi performance head flow database is an excellent tool for head selection. I looked there but couldn't find 802s in it. Corey68 has a pair of 990s for sale in the parts forum that he wants 900 skinz for. Although not alum, they're some pretty good heads according to the chp data.

Brett :thumbs:

Summerfun

These are the heads you want!
http://cgi.ebay.com/ebaymotors/ws/eB...spagename=WDVW

I have a set of those that I used on my LS6 and later LS7....they are great heads. They made a lot of power in that LS7.....11's

I have them on the shelf now (not for sale) as I went with Dart Pro 1's when I went to monster cubes.

Here is another I found....i didn't check into their specs though.... http://cgi.ebay.com/ebaymotors/ws/eB...spagename=WDVW

Summerfun

BTW, check out those 3946074's on that website you mentioned in your first post.....they were the good ones 35 years ago!!

My only two problem with those 35 year old heads:
1)Not T6 aluminum
2)Valve seats can vibrate, come loose and cause the valve to jam, snap off and beat up your head and piston.....not that it happens very often at all!!!

When you get something like that in the back of your mind though, it will drive you nuts!!