Hello all,
I'm new from Rockwall, Texas. I have an 85 C10 with an early 97/98 perimeter head bolt ls1 in it. I have a few sets of 243 heads but I am trying to figure out what the best head gaskets for this combo would be. I googled and searched this site and found numerous threads but haven't found the answer.

Thanks guys

 

GM MLS head gaskets are usually what everybody goes with...

 

I noticed two different ls1 5.7 head gaskets. Should I go with the ones said to be specific to the earlier ls1's?
Thank you btw, wasn't sure if that would be a good choice based on compression differeneces.

 

you may have to mill the heads slightly to make up the difference for the gasket thickness

 

There's 2 gaskets. Graphite, and multi layer steel. If you've ever cleaned the deck surface after removing 241's or the like, you'd never use graphite again. Go with the .051 compressed thickness GM MLS gaskets, or preferably the Cometic .040's

 

Thanks guy, I appreciate the guidance.

I found some cometics on Ebay. Roughly $75-80 for each head. $150ish for the pair.
Would these be the correct ones you were speaking of?




Manufacturer: Cometic Gasket
Part Number: C5475-040
Condition: New

Product Description:

MLS (Multi-Layer Steel) Exhaust Gaskets

Additional Information:

Description: GM LS1 SB 3.910" BORE

Long Description: .040" MLS



=============================================

 

That'd be them

 

Good thing I got the heads for free!
The gaskets aren't cheap!

 

Save some coin:
http://www.summitracing.com/parts/nal-12498544

 

you mentioned "you had a few set of 243 heads"? Lol Hope it works out for you.

 

I buy, trade and sell alot!!!! I have twelve cars and trucks now. My dad recently passed away in april, i inherited another house, his first car.. 66 Chevy II 2 door hardtop. 64 & 65 Coupe Devilles, a few others. My first truck was an 85 C10 black on black, he also had an 85 C10 black on black. He bought a complete low mileage ls1/4L60e that he had planned for the Nova, and it will go in there soon. I stuck the ls1/4L60e into the C10 so I can get all the ls swap done with the complete motor/trans for now. I ended up with an aluminum 5.3 L33 motor, a set of 243 heads and TBSS intake off of an '07 5.3 and sold the dod 5.3 short block. Plans for the 85 C10 that was mine are to eventually pull the ls1 out and put the L33, tbss intake in since the intake will clear the hood and the ls1 will look better in the Nova that was his anyhow. I'm going with a 4L80e with a stall from Circle D in the C10 as well. Trying to pick a cam out before I get the stall. I have a brand new box of pushrods, Lunati double valve springs, 2 sets of 243s, and two sets of LS7 lifters. After the 85 is done, The Nova will be Next! I have been a member of LS1truck.com since 07 but it is fading away.....

 

Sorry to hear about your Dad, pretty kool that you plan to carry on his plan with the Nova though. I had to ask about the 243 heads in case you were some hoarder with a hidden stash as Im starting to look for a set for my 99 Camaro SS now that im out of school and can finally afford to mod my car.

My step brother will eventually be in the same situation as you, he is set to inherit 2 56' Chevy 210 ( one Nomad, other full dress package) and 1955 or 56 Bel- Air from his grandfather.

 

My dad was a hoarder... Car parts and too many cars haha. Not too bad though. His best friend has a '57 Bel Air, and about 20 tri-fives if your step brother needs parts let me know.

 

Haha will do. His Grandfather use to drive the mayor around during the Rise Bowl Day Parade. Let me know if you ever come across another set of 243 heads tucked away ;-)

 

I bought a 71 C10 with a reworked ls1. The fool overheated it and warped the heads. I had them decked and put it all back together with a MLS, whole kit from Texas speed for $350, great deal. Anyway, it was the cheapest route but 243's are boring and don't get my longbed moving fast enough. If I could go back in time I would get a credit card, some afr heads, and a bigger cam! Have fun with the build!

 

This ls1 will be mild for my 66 Nova, I have a L33, going into the C10 after I get the ls swap completed. I bought now have two 4L80e's so I need to hit Circle D up for some stalls. Got my wiring harness from PSI. Should be dang near done. I have to decide on what I'm doing for a fuel system then I should be rolling around in the C10 again.

 

I have always wonder about milling heads. Does that screw up bolt hole alignments and mating the intake to the heads as well throwing intake port runners off. IMO that would be a lot of problems when doing mill work on the heads.


Spend more money milling heads and port work to try to perfect everything. Why not just buy new bare factory GM heads. I think the GM head is only $399 for a bare head. Add your valves, springs and other stuff.


Maybe I am missing the true purpose between milling and buying a new bare head.

 

Buying brand new heads doesn't gain anything unless the ones you have are cracked. The purpose is to reduce combustion chamber size and increase compression. The .020" or so you would mill them won't affect bolting up the intake at all. It will make for improved throttle response and mileage.

Many people do this on a budget and then go back for more a second time. Be honest with yourself. If you are going to want the motor to scream, you need to invest in the heads. You could send them to PRC for porting and be better off. You can call Tony Mamo for heads and all the supporting stuff and know you haven't left anything on the table. Tony can make 500 horsepower daily drivable if that's what you want.

If you want to be in the 350-400 range, the 243 heads are great.

 

Thanks for the reply! Yeah what you say makes sense. What kind of heads would put a LS1 in the 550 to 600 HP range?


Also on the 243 heads, is there a cam that would put it over 400 HP?

 

Answer to your first question is to call Tony Mamo. I know his MMS220 will hit 500 to the wheels on stock cubes. I wouldn't know where to start to hit 550-600 on stock cubes to the wheels. 600 at the flywheel is about 500 at the wheels if that helps.

Pretty much any cam in the 227-233 intake duration range can get you over 400 with 243 heads and other supporting mods (intake, headers)