half-fast

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?

jeverett

Have you tried some 350 heads? I've been told they work good, but I dont know personally..

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half-fast

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.

wilfie27

What is the casting number on the heads.

Sorry so late