Recommended head gaskets for mild build

[2sloUknow]

My 85 ttype is getting a mild build with ta33c, fuel hot wire, walbro 340, blue top injectors and a new 140a alternator. I was going to go with RJC gaskets, until I read the directions for heat and retorque 10 times. Getting to the passenger head under the turbo is a pain once, not doing it ten times. So I am leaning towards cometics. The bottom end and heads are stock with 80k on the clock. What thickness gasket is recommended? Should I go with stock gaskets instead? Any advice and opinions welcomed.

Thanks!

 

[Jerryl]

Stock gaskets may be a challenge to locate. Agree with the PITA retorque statement though.

Gasket other than stock thickness can potentially cause all kinds of alignment issues such as: Intake bolts, turbo up pipe, cross over, lifter preload, DP, etc. All should be inspected either way.

So while the stock thickness is the least troublesome, you want the highest CR you can get away with for both mileage and performance. Typically very difficult to get over 9:1 with stock parts anyway. If the heads and block are decked, install felpro 9441 or look into felpro 1000s. Good luck.

 

[crashedout1]

I think the 85 head bolts arent reusable. Might want to check that also.

 

[2sloUknow]

I think the 85 head bolts arent reusable. Might want to check that also.

I never reuse head bolts. Most are torque to yield. I always replace with studs whenever possible, as is the case here.

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[crashedout1]

I thought the 84 bolts were reusable. Im sure most people replace them im no expert.

 

[2sloUknow]

After some research and asking around I've decided to go with the cometic MLS .040. Now to clean these Damn heads and block. I've heard since they are iron I can use rolocs. I've also been warned against that. I'm going to gently scrape and then block sand. Going to damp sand with 220 then 400. Can I go coarser?

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[Jerryl]

Not sure if the block is pulled and not trying to discourage you but . . . . MLS requires the heads and block to be flat within 0.002 with a minimum surface finish.

I would also not recommend the use of abrasives unless you plan to completely disassemble and hot tank the block. Even if that is the case, the deck will never be true and finish will not be where it needs to be.

Heads need to be inspected for flatness and surface finish as well for MLS to work successfully.

 

[Jerryl]

Final comment before bowing out of this thread.

I run the MLS 0.040 on the HA and they do not leak or seep. Great gasket. What blows head gaskets on these cars is *typically* not a result of gasket integrity. Typically it's uncontrolled combustion, and assembly errors. Just like BBQ, there are 1000 recipes and there are lots of options with head gasket replacement.

Would just hate to see you get discouraged. Good luck whatever you decide.

 

[2sloUknow]

Final comment before bowing out of this thread.

I run the MLS 0.040 on the HA and they do not leak or seep. Great gasket. What blows head gaskets on these cars is *typically* not a result of gasket integrity. Typically it's uncontrolled combustion, and assembly errors. Just like BBQ, there are 1000 recipes and there are lots of options with head gasket replacement.

Would just hate to see you get discouraged. Good luck whatever you decide.

That's my intent. Do it right. One time. I plan on using the 85 as my almost daily as I rebuild my 87 basket case. Thanks for the info jerry.

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[Nick Micale]

The 1984-5 used stock steel head gaskets which are 0.018".

If you need set, I have some GM originals on the shelf.

 

[2sloUknow]

The 1984-5 used stock steel head gaskets which are 0.018".

If you need set, I have some GM originals on the shelf.

Nick, I sent you a pm. Thanks.

 

[hotairgnx548]

Nick, I sent you a pm. Thanks.

nick how much would 2 shim stock hot air head gasket cost? john

 

[Nick Micale]

They cost me $50 each from GM, pay the shipping and you can have them for $110.

 

[hotairgnx548]

thanks nick i'll tell my guy. john