Brians1

Guru's,
Need some parts help.....

** I do not have the budget this year for a new engine, nor a top-end kit. I also have a 2 and a half year old son so I do not want to spend hours over many weekends turning wrenches just yet...waiting for my son to get older to do that


I have several bent valves and a few rocker arms all out of wack....engine is running like crud under load and inst performing well (well in terms of the 190HP she had....LOL)

This being the case, my L81 w/ 86K miles sits as follows:•CCC 100% operational - no error codes
•E4ME Carb - fresh rebuild from National Carbs
•MSD Coil, Cap, Rotor, MSD 8.5mm Plug Wires
•Accell Ignition Module (MSD doesnt make a 7-PIN..Accell Does)
•Corvette Central True Dual Exhaust Kit (* No Cat - straight duals to H-pipe to Magna Flows)
•Stock L81
•Compression test completed (155-162psi) accross all 8 cylinders

All I want to do is get thru the rest of this year with a running engine while I work on saving for a new motor

I am looking for help in choosing either a Summit Racing brand or Chevy performance brand cast iron "facotry replacement" head.
And again I fully understand performace, etc, etc but its not in the budget now...just want to keep it driving for the rest of the year.

When I searched Summit for my 1981 350 5.7, for the chevy perf brand I saw a lot of "Vortech" verbiage, etc (One option here). I just want to make sure I choose the correct bolt on heads, that will also fit the patriot headers that i got from the exhaust kit....per the details on the headers fitment:

Fits D-Port cylinder heads including ZZ4 crate engines. Also fits Dart-S HP Heads (** Hint here - I am saving up for a ZZ4 **)
Will NOT fit:
* GM 340292 "turbo" or "bowtie" heads
* Airflow Research (AFR) heads
* Trick Flow (TFS) 195cc with D port heads
* Aluminum heads from Blueprint Engines
* Dart Pro I
* Dart II/Sportsman

gerry72

I would probably be inclined to shop local on this and see what a machine shop may have on hand for you. That would be your cheapest route for completely stock performance. If you want to spend a bit more, there are a variety of cheap aftermarket iron performance heads from Jeg's, Summit as well as others that would do fine on a ZZ4.

You want to avoid the Vortech stuff unless you are also willing to do an intake manifold swap to fit the heads.

How are you getting 160psi compression and relatively even on all eight cylinders with bent valves?

Brians1

Thanks for the reply....to answer the Q on the compression, not really...The cylinder with bent valves are off a bit....my math on if the valves were sealed properly....

I am ok with spending a few hundred bucks on a "bolt on set" such as Summit or Chevy performance.....and thank you for confirming the Vortech comment..i was 99% sure thats what I didnt need...

AirBusPilot

If you only have a bent valve or two, pull the heads and get a couple of new valves and valve job. Cheapest route. Just don't have them do a total rebuild of the heads, if you want to save money.

Though I'm wondering what caused the bent valve to begin with.

Flyinace3

I have a new unused set of gm iron 76cc heads from a Goodwrench 350. PM me if you are interested

LannyL81

The problem with getting the stock heads fixed is that there is a 98% probability of them being cracked due to the light casting.

I would not waste the money on them.

Check your local machine shops or craigslist for a pair of chevy 882 heads; will bolt on with no modifications. Just use a new set of head gaskets.

Be advised that the iron heads are heavy and take care lifting them off the car...protect the body and even better have a helper. Same with putting heads back on. Easy to get off balance and into trouble quickly.

Good luck and let us know what you do.

qwank

buy some zz4 or trick flow 175 heads now, and when you're ready for the engine, buy the ZZ4 short block and swap the heads over

Brians1

Thanks guys. Im working behind the scenes with Flyinace3 from his offer above, he purchaed a GM crate engine and swapped out the iron heads for better aluminum ones. These GM Cast iron heads would be a direct bolt on "replacement", and I wouldnt be spending any kind of money to make the boss (aka wife) upset. This is pretty much what I was after...very very cheap and will def get me buy to enjoy the car for the rest of this year.

qwank

so how did you bend your valves?

Brians1

well I didnt LOL...with all the other crazy things the PO did...I'm not sure what he did, but he was able to do a lot of bad...

63mako

We have a winner!

scottyp99

There ya go. If Flyinace3 will part with these heads for a good price, you're in business. Only question is: what's it going to cost to ship two iron heads from Michigan to Florida?

Scott

hugie82

Finding the heads is the easy part but I would use extreme caution if you have valve train problems. Most people with low compression engines never have a bent valve or blown head gaskets because the motors just don't have the power to cause that kind of damage unless severely overheated!
I would have someone check out the cam lift on all the lobes. If you have a wiped cam, heads will do nothing but add to the cost.

Flyinace3

76cc chambers 1.94/1.5 valves, With the pushrods and valve covers.

Brians1

Do you guys have a suggestion in what head gasket to run with these heads ?
Would this work well ?
http://www.summitracing.com/parts/fel-1094

Brians1

Well I did some digging on that crate engine that Flyinace3 purchased, this is the head gasket used so I will purchase this one:
http://www.summitracing.com/parts/nal-10105117

qwank

either one will work, the first one you posted will bump your compression up slightly, however, I'm not sure how reliable the shim style gaskets are. Although it seems like a lot of people on here use them

REELAV8R

Go with your first choice the 1094. The second one you listed is .028" thick. Too much squish distance with the piston the stock .025" down the hole already.
Shoot for .040" squish total.
Might want to wait till you have the heads off to see what you have before ordering the gasket unless your sure it's still a stock deck.

A guess on what happened to the valves and pushrods with the engine is that it was either over reved or rockers misadjusted. Either one would have had the piston contacting the valve.
Check the pistons closely while you have the heads off.

Brians1

Last Q...I have my 81 Shop manual..I assume I should just follow its reccomended torque LBS and sequence - no devation I assume from 1981 till now on the "how to"

REELAV8R

Yes, no difference as far as I know.