My 87 puked another head gasket, second time in 3 years. Long story, save the drama.

I want to go to cast iron heads. Any advice on what will swap over is greatly appreciated.

No, I'm not going to try the aluminum heads again.

 

The best iron heads are the casting number 3998993, usually called "993". Combustion chambers: 76cc. 1.94 intake, 1.50 exhaust valves. Stay away from the later 462624 "624" heads. They are a lighter weight casting (3 1/2 lbs.), and are subject to cracking.

The 993 heads didn't come with exhaust valve rotators (624 did), but can be easily upgraded. The 993 has larger internal water jackets, too.

 

I don't have the problem, but I'm curious if all the things like TPI etc will bolt up with those heads or not? I like knowing options in case it ever happens.

 

let me throw this into the mix. pretty common for AL head L98's to blow the head gasket at either #7 or #8 cylinder. on my 90, I had a rear china wall leak, and during the repair, I used a gasket set (fel-pro) for a standard iron head SBC. these gaskets have an open rear cooling port vs. the restricted type used on AL head L98's. I did keep the standard steam tube. for some reason, Chevrolet added a restrictor and a STEAM tube to these engines. the use of the term "steam" used anywhere in a cooling system bothered me. I did a little forum search and found several folks have done this without issues. anyway, long story short, coming up on three years now and about 10K miles, and zero issues. all temps seem to be normal. you JUST might want to try using another manifold gasket set. it could save you a $grand or so on repairs.

 

It might be a good time to consider an upgrade.

One I have heard good things about is the Vortec heads with a new tpi baseplate. On a stock L98 it is supposed to bump hp up 50 hp to about 300 hp. They are pretty reasonably priced compared to other heads.

I have put a couple of links below. Note that there are several other vortec head options such as for higher lift with better springs, etc.

http://sdparts.com/i-23896057-sdpc-s...baseplate.html

http://sdparts.com/i-19958322-chevro...assembled.html

 

if you use a earlier L 98 Corvette ironhead set, I think you will need a new set of valve covers. My 87 has the center valve cover mounting bolts where is my 85 iron it has four bolts around the perimeter on the corners, I will also have a look to make sure that the plumbing lines up the same too. also will u need to add cost of new alignment?


hylomar with decking the heads/block may fix it.


i just did my iron head head gasket. blew at 7. did u deck your al heads both times?

 

on my 90, I didn't pull the heads, I only had a rear china wall leak. I suspect it recently had a head gasket issue/repair, and the rear leak most likely due to poor mechanical skills by the previous mechanic. anyway, fixed the leak - so far, so good....

on my iron head 85, no (professional) shop work. I checked for flatness, checked and inspected valve guides, and valve seats. as for flatness, I could not detect anything over .002" (standard 5-way check). I cleaned the heads and did some minor port clean-up. spent several hours, carefully inspecting for cracks - nothing. on the valve guides, I had two guides out of spec - spec at .0028 max - I had one at .0033, an one at .0037. I did not have any issues before I tore the engine down, and performance seemed quite good for a 150K mile small block, so just threw in a new set of stem seals. I did have one valve seat that seemed questionable, but it didn't appear to be too bad. the seat face on my exhaust valves were questionable, and I had one intake that need to be replaced. I opted to throw in a new set of elgin I/E valves w/ new springs. all the valves lapped in perfectly. long story short, after 800+ miles, everything seems fine, performance as good, if not better than before. no oil issues, no cooling issues, nothing! best part, I didn't have to run these thing through a machine shop - i'm thinking it's around $200 for hot tank, magnaflux, and pressure test. because of the valve guides, the shop would want to replace all 16 valve guides, cut new seats, and replace valves and springs. I most likely would be looking at hundreds of dollars for a valve job. I didn't want to spend a bunch of money on heads at this point in time on an engine with 150K on the clock. I've done valve jobs like that in the past - back in my early years when I had no money for fancy shop work. back then, I was lucky I could put gas in my cars!

BTW, if anyone is interested, these are the valves/springs I used. I know they're cheap, but I took a chance. to be honest, I thought the quality was very good. comparing the valves to GM NOS valves I have, I thought they looked damn good, in fact, maybe better. elgin is a tier (1 - ???) supplier for GM, so there's a chance these are the same as current OE and service replacement parts.

http://www.ebay.com/itm/New-Z28-Springs-1-94-Intake-1-5-Exhaust-Valve-Set-Chevy-400-350-327-283-/221595439283?hash=item33981e10b3

 

There are 2 new iron Vortec Bowtie heads released on February 12,2016

19331470 Small port 185 intake 65 exhaust 66 cc chambers

19331472 Large port 225 intake 77 exhaust 65 cc chambers

Both feature dual bolt patterns, light weight valves, and LS style springs intended for iron head racing classes.

 

I really like my World Products Torquer II's. But had'm pocket ported and the vlvs unshrouded. They are only 67cc chambers though. If u want 64cc iron heads u have to looke else where like Dart iron eagle or RHS has some nice heads too but i never owned those so take it for what it worth (not even 2 cents).

Hope this helps.

 

I thoguht they had discontinued those or at least the 185...interesting that they are said to be out again. Good cast iron head for sure.

 

Engine Quest (EQ) has a great Vortec replacement cast iron cyl head with the old style intake bolt pattern....

PN CH350H

I would just buy the bare castings and transfer all the studs, guide plates, valves, springs, retainers and locks out of your 113's over to them.

http://www.competitionproducts.com/E.../#.VxjNrZ3D_IU

But you can buy them turn key with all new componets.

http://www.competitionproducts.com/E.../#.VxjOaJ3D_IU

Will

 

WTF, so let me get this correct. The OP is going to go from a 58cc head to a larger combustion chamber and lower compression for less power? Maybe I need to smoke crack?

 

What FelPro # ?

What is a "steam tube" ?

 

Since you have an 87 center 2 bolt hole angle changed. You want to be sure what you pick will work with intake or you will need to modify those bolt holes on intake.

 

L98 heads remained 90 degrees through 91.

 

tom - I had a fel-pro manifold set for a 85-92, 305/350 GM V8, part number MS 93035-1. can't remember where I got it - either fleabay or summit. anyway here's fleabay link to the fel-pro kit -

http://www.ebay.com/itm/Engine-Intak...dVrsry&vxp=mtr

"steam tube" -- there's a small metal tube (and fitting) that comes off the rear, RH side of intake manifold - near the distributor and EGR exhaust tube. that tube connects to a section of hose. I think the correct GM terminology for that assembly is "manifold vapor tube." I've always called it a steam tube.

 

I always thought it was to bleed off air in that port?

 

could be - I have no idea why it's there or what GM's thinking was on the restrictor and tube. I can say, that after I installed the open port gaskets, I had a constant of coolant flow from the manifold to the coolant reservoir. anyway, kept the tube, installed opened restrictors, and so far no issues - everything seems normal.

 

Okay.... thanks... got it. I have to replace that tube because it's all rotted out.

I have a Fel Pro set 1205S-3 on the shelf for my 383. Maybe I'll use that set.

 

ts not just a question of buying Vortec heads, as good as the are. You then have to buy a manifold that fits them. I bought a rebuilt set of Vortecs from a machine shop, 300 bucks. The real money spent was on the Elebrock manifold and high flow runners. Almost a grand.