Ransford2987

I have a 1990 L98 and I have a leaky valve guide seal. It's on the passenger side head, and I know I don't NEED to have both rebuilt, but I'd like to get them done anyway while I have some time off in July. I'm not swapping a cam or anything else, and I'm trying to keep it as original as possible. I'm looking to get the parts before I send them off to the machine shop. Here's what I know about the stock heads:

1.5:1 Rocker arms (can I go 1.6? What has to be done?)
Spring pressure: 80 lbs closed/200 lbs open
Spring height: 43.7 mm Intake/40.5 mm Exhaust
Valve Lift: .415" Intake/.430" Exhaust
I'm assuming 1.94/1.50 valve sizes?

I'll replace anything that needs it, and I'll upgrade wherever I can. What do you guys recommend for Valves, seals, lifters, rocker arms, machine work, valves, head gasket, etc.?

As always, if there's another thread with this info, let me know. I couldn't find one doing a mostly stock rebuild. Thanks in advance!

LB9GTA

iTrader: (1)

First question?
How much money do you want to spend?
Do you want to go faster or just fix the problem?

If you have no budget, fix the problem and put a stock head gasket back in.

If you got cash, buy a new set of heads, get 1.6 roller rockers and a thin head gasket.

Ransford2987

I'm somewhere in the middle I guess. I'd like to spend around or under $1k, and mostly looking to 'improve' what I have already. I'd like to rebuild these more for reliability and never have to worry about them again, and also add some upgrades or improvements wherever possible. I'm not looking to push the limit here as this is my daily driver.

LB9GTA

iTrader: (1)

Are they still the stock springs? Maybe time to replace them
Maybe time for new valves.
Best would be to shop around and get a price in your mind to know what you are spending.

Get 1.6 roller rockers. Good for a couple hp and make your cam slightly bigger.
Thinner head gasket (slightly more hp and compression)

Drac0nic

For 1K look at a myriad of the aluminum heads out there you are in entry level territory for a good set of heads.. Otherwise get valve springs, positive seals for int and exh (kills the smoke puff) and a good valve job. With the guides that should keep you going for a long time and add a couple ponies.

Ransford2987

Will 1.6:1 rocker arms fit under the stock valve covers?
I know I have to increase the height of the spring to accommodate the larger ratio:

Check my math here....

(rocker arm ratio)x(cam lift) + (.05") = 1.6x.273+.05" = .487" total travel (intake)
1.6x.282+.05" = .501" total travel (exhaust)

If i understand this, this should be the actual height of the spring installed with the intake valve closed. Doesn't this increase the total installed height of the spring? The intake installed height from my manual says 1.7", with .415" lift. So adding .072" to the spring, I would have an installed height of 1.772"? Will that fit under the stock covers Also, does anyone know the spring diameter?

What pressures do you guys recommend for springs?

RyanJB

Can't go wrong with Comp valve springs. If you'd really be interested, you could get your heads cut for 2.02/1.60 valves, which would also free up some ponies.

Ransford2987

The 2.02/1.60 valves are the plan, unless I'm told they won't work. I don't know the capabilities of the stock heads, and I've never had any of this work done before.

From what I'm getting with a google search, stock spring OD is 1.25" with a max of 1.265" without machining. I don't know what height or pressure I need. I've read that too much pressure can wipe a cam, while too little has valve float issues.

My thought here, installed height - bind height needs to be > .502" to allow for full valve travel. Perhaps these:
http://www.summitracing.com/parts/cca-982-16/overview/

And what about these lifters and rockers:
http://www.summitracing.com/parts/cc...make/chevrolet
http://www.summitracing.com/parts/cc...make/chevrolet

Last queston (for this post anyway), will I need knew studs due to an increased rocker arm ratio/valve lift?

Ransford2987

The more I add these numbers up, the more it just makes sense to buy some aluminum heads...ugh. Has anyone used these: http://www.summitracing.com/parts/ed...make/chevrolet

If I do go this route, couldn't I use 1.65:1 or 1.7:1 rocker arms with the stock 5.7 cam?

cuisinartvette

Most when putting larger valves in those 113s go 2.0 int
It doesnt get you much really you made a good decision esp cost wise to get some new ones. Not a fan of 1.7 rockers on sbc just get a little larger cam keep your 1.5 make it easy on yourself

LB9GTA

iTrader: (1)

I put 1.6 rr underneath stock valve covers.

Ransford2987

Thanks for the help guys. Fitting 1.6 roller rockers is a must, as I'm really trying to keep the stock covers. Any suggestions as far as aftermarket aluminum heads while still keeping ~$1k for the budget? The only ones I see that are a direct fit for TPI under $1k (while leaving some budget room for lifters and rockers) are the edelbrock performer heads. I see the ZZ4 heads, but they have 1.94/1.50 valves and don't come with valve guides..but they do have 58cc combustion chambers. Still, I'm leaning towards the performers

http://www.summitracing.com/parts/na...make/chevrolet

http://www.summitracing.com/parts/ed...make/chevrolet

Tuned Performance

iTrader: (92)

http://www.ebay.com/itm/1987-Chevy-Corvette-350-Aluminum-Cylinder-Heads-NEW-Manley-Valves-Isky-Springs-/191085129002?pt=Motors_Car_Truck_Parts_Accessories&hash=item2c7d8fad2a&vxp=mtrhttp://www.ebay.com/itm/Small-block-Chevrolet-aluminum-heads-fit-283-327-350-383-400-ZZ3-/331139583573?pt=Motors_Car_Truck_Parts_Accessories&hash=item4d19750e55&vxp=mtr

Orr89RocZ

iTrader: (20)

They could work or a set of shp 180's for abit more, 1160-ish

Or jegs brand 180's for 1070$

Tuned Performance

iTrader: (92)

Don't spend the money on new zz4 heads, listen to Orr or step up to afr 195s or even a good used set of trick flows or eddys in the $8-900 range.

Ransford2987

I found these on the trick flow website. Not sure if this is what you were referring to, Tuned, as they are cheaper, but they seem better than the edelbrock performers for about the same price. One question I have: do these head accommodate the (2) 73* bolt holes for the TPI base?

http://www.summitracing.com/parts/tf...-m64/overview/

I found these also, but they seem to be too cheap for what you guys are referring to... http://www.summitracing.com/parts/drt-127322/overview/

Tuned Performance

iTrader: (92)

IMO if your looking a new go for Afrs , the summit brand I think are the same as bodix. I think the 200cc a stock intake may not cover the top of the intake runner. Unless your going to port your intake of get a aftermarket base that will be your choking point. If not stated the intake pattern you can always elongate the inner 4 holes of your manifold. I personally wouldn't put over 400 in rebuilding the stock heads. Spending more now will be a good start
Power upgrades when a cam is installed. nothing wrong with the 083 heads but weight savings and better flow is worth the extra money.
You never know about used heads allways assume the worst that they need to have new springs or a valve job or the guides maybe wasted. I'm going to have to spend a few hundred to make right. I have good morals and won't pass the bad luck to someone else.
https://www.thirdgen.org/forums/engi...eads-sold.html

Ransford2987

I'm pretty set on buying new, mostly for that reason. I don't want to invest in something that I'm not sure of, or have to take someone's word for, when it comes to condition involving precision measurements and tolerances. I have the money to buy new, and that's the plan. You're right regarding the stock head rebuild. I wanted to keep it as 'original' as possible, but it just doesn't make sense to spend that much on a lesser performing head.

I was hoping I wouldn't have to elongate the 4 bolt holes on the intake, but I guess I can look that up to see how difficult it is. Does anyone know off hand how large of an intake runner I can go with a stock TPI base? Orr mentioned 180's, so I assume they will fit.

On another note, what aluminum 1.6 roller rockers and what lifters do you guys recommend. I see so many, and it's not clear where some outperform or are better than others.

Orr89RocZ

iTrader: (20)

Stock base dont go over a 1205 gasket. I dont know what the shp or jegs 180's heads are however

Ransford2987

The 200cc's Dart SHPs recommend a 1205 gasket as well, so does that mean they will fit the stock TPI base? I tried looking this up, but I can't find the largest intake runner size I can run on a stock TPI base.

Orr89RocZ

iTrader: (20)

Its the gasket size you need to worry about. Stock base doesnt have enough material to properly cover a 1206 and barely covers a 1205 after porting.

If the head takes a 1205 gasket then good to go. Most sub 200cc heads are 1205 but alot are 1206. Dart shp 180's are better than 200's

Ransford2987

Thanks Orr, that's good to know. I'd like to get all of these parts over a couple months to lessen the blow to my wallet, and I don't want to overlook some specifics. I'm not porting my TPI base, so the 1205 intake manifold gasket should definitely work. Any suggestions on head gasket thickness or head bolts? Should I replace my head bolts? I'm thinking yes, but don't know if I should go stock replacement or ARP? I'm not sure ARP's are necessary for slightly better than stock components.

Orr89RocZ

iTrader: (20)

With pistons in the hole abit, i'd try for a thin gasket. .025-.030 if you can find one. Mr gasket or gm made a nice composite .028"

Bolts i dont think it matters in that build.

Ransford2987

Anyone have a link to a thread discussing elongating these 4 middle bolt holes, maybe with some pics? I've read a few but looking for more details; I don't want to screw this up. Is the 73* angle in references to the plane of the head/intake surface (so 90* is perpendicular to it)? Also is that 73* up from inboard or outboard.

Here's my parts list so far; let me know if I've ordered something that won't work or if I've forgotten something.

CCA-7702-1 Pushrod checker
CGT-C5299-018 Water pump gaskets
FEL-1204 Intake manifold gasket
FEL-1404 Exhaust manifold gasket
FEL-MS93160 Upper intake gasket set
NAL-10105117 Head gasket
NAL-12337972 EGR gasket
11746-16 1.6 Crane Roller Rockers
127122 Dart SHP 180 Heads (Out of all the recommended heads, these were the easiest to afford while still aluminum and with the right specs)
I know I still need lifters, but I haven't decided which ones yet. Any thoughts?

Thanks again for everyone's help!