-
Grand Future Air Dried Fresh Beef Dog Food
Air Dried Dog Food | Fresh Beef

Carnivore Diet for Dogs

Go Back   Automotive Forums Car Chat > Chevrolet > Avalanche | C&K | Silverado | Suburban | Tahoe > C/K
Register FAQ Community
Reply Show Printable Version Show Printable Version | Subscription Subscribe to this Thread
 
Thread Tools
  #1  
Old 08-12-2004, 09:08 AM
half-fast half-fast is offline
AF Newbie
 
Join Date: Feb 2004
Posts: 65
Thanks: 0
Thanked 0 Times in 0 Posts
86 305 cracked heads substitute?

I have been battling the emissions on this for several years now... and come to the conclusion that I might have cracked heads. According to all the books, the 86 could have the thin casting, double passage crossover heads that are prone to cracking. So... I am going to pull them & replace. Problem is, I don't know what to replace them with. I think they are low compression 76 cc chambers.

I pulled the engine, sandblasted the block, heads, pan, valve covers etc, had the block bored and installed new pistons, rings, bearings etc. Did a 3 angle valve job on the heads, didn't see any cracks when lacquer thinner was dumped on the heads. I have valve refacing & seat cutting equipment, but I do not have a magnaflux setup and I did NOT have them magnafluxed.

I replaced the Q-Jet with a brand new Holley 80555 and re-engineered the vaccum hoses to run the emissions equipment, and I used a 1980 Vette EGR with a little mill work to fit. It runs, barely. So... with all of the emissions equipment disconnected, with only the vac advance connected (no other vac lines connected, no power brakes) and with a Accel HEI distributor (no ECM etc), and new intake gaskets, the engine runs like it still has a massive vaccum leak. Compression is good, and even. So I'm taking an educated guess that the heads are cracked internally as suggested by all the books.

I am about to buy some Edelbrock heads from Summit Racing, but I woud like to know if there are alternatives. Replacement rebuilt heads from Autoparts stores are not an option.... the chances are too great that I would end up with another set of thin casting cracked heads.

Anybody replaced the heads on their smog 305 with aftermarket heads and still pass a sniffer test? What did you use?
Reply With Quote
  #2  
Old 08-12-2004, 10:17 AM
jeverett's Avatar
jeverett jeverett is offline
AF Enthusiast
 
Join Date: Sep 2003
Posts: 2,154
Thanks: 0
Thanked 0 Times in 0 Posts
Send a message via ICQ to jeverett Send a message via AIM to jeverett Send a message via MSN to jeverett Send a message via Yahoo to jeverett
Re: 86 305 cracked heads substitute?

Have you tried some 350 heads? I've been told they work good, but I dont know personally..
__________________
1998 ECSB Z71
Whelen LED's
Kenwood 2-way
"BIG 3"
2500+ watt audio

Reply With Quote
  #3  
Old 08-12-2004, 03:18 PM
half-fast half-fast is offline
AF Newbie
Thread starter
 
Join Date: Feb 2004
Posts: 65
Thanks: 0
Thanked 0 Times in 0 Posts
Re: 86 305 cracked heads substitute?

The edlebrock heads I am considering are "small block Chevrolet" which includes 305 - 350. The only issues with these is that the large valve heads may require relieving of the cylinder block walls for valve clearance due to the 305's smaller bore. The real question I have is.... has anyone successfully replaced cracked heads on a 305 and still pass emissions testing? If so, which heads were used?

I really don't want to spend $1000 on heads right now.

I'm having a real tough time with emissions tests.

I'm in NC and they have a computerized system that tracks emissions failures/un-inspected vehicles.... and they mail you a $250+ fine if your vehicle is past due. I had to take the truck off the road twice to clear the fine in-progress. They don't have to "catch" you on the road. It's all done by computer. I put less than 1000 miles on the truck each year, but I still have to deal with this BS.
Reply With Quote
  #4  
Old 09-08-2004, 03:42 PM
wilfie27 wilfie27 is offline
AF Regular
 
Join Date: Aug 2004
Posts: 141
Thanks: 0
Thanked 0 Times in 0 Posts
Re: 86 305 cracked heads substitute?

What is the casting number on the heads.

Sorry so late
Reply With Quote
 
Reply

POST REPLY TO THIS THREAD

Go Back   Automotive Forums Car Chat > Chevrolet > Avalanche | C&K | Silverado | Suburban | Tahoe > C/K


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 08:55 PM.

Community Participation Guidelines | How to use your User Control Panel

Powered by: vBulletin | Copyright Jelsoft Enterprises Ltd.
 
 
no new posts