Best GM Vortec intake manifold gaskets?

[MikeB]

Would like to hear recommendations for intake manifold gaskets to fit GM "062" Vortec heads and Weiand 8121 Street Warrior manifold.

[CGT]

I've been using Fel-pro 1255 intake gaskets the last couple times. They overhang a bit here and there, but if glued down they don't take much time to trim up. They are .125 thick if you need that thickness for port alignment.

I think GM#89017465 O.E gasket is probably the overall the nicest and best chance of sealing long-term, but I don't like the way they fit personally.

I have had a little trouble sealing up that vortec pattern on the dyno here and there.

I now put a skim coat of rtv sealer around all the intake ports for safe measure. There just isn't any bolts in that area to really push the manifold against the gasket, and the ones on the end are vertical. They just essentially keep the manifold from flying off the engine.

Depending on if your entry is stock in size etc, there is also Felpro 1289 .0625 thick I believe, but larger square opening. If you call Cometic they can burn you some gaskets off of any of the Felpro numbers yet in any thickness you desire pretty much.

[CGT]

Resized_20190307_181700.jpg

1255 intake gasket trimmed to fit

[F-BIRD'88]

Also prefer the felpro 1255 for vortec heads.
You WILL need to hand re tighten the bolts a few times, especially on any new manifold.
Same as new headers....
No leaks or fuss here. Only use Black RTV on the water ports and China Walls. Can put some vaseline or white gease on the gasket if you want to R+R reuse to keep it from sticking.

[In-Tech]

Hello,
If the heads are cut and you don't want to cut the intake manifold, BLP has these. Most Vortec intake gaskets are ~.125" thick.
https://blp.com/cart/index.php?main_pag ... ts_id=1052 These are .031" thick
http://blp.com/cart/index.php?main_page ... ts_id=1053 These are .047" thick
https://blp.com/cart/index.php?main_pag ... ts_id=1054 These are .062" thick
https://blp.com/cart/index.php?main_pag ... ts_id=1055 These are .095" thick
http://blp.com/cart/index.php?main_page ... ts_id=1056 These are .125" thick

[CGT]

Hello,
If the heads are cut and you don't want to cut the intake manifold, BLP has these. Most Vortec intake gaskets are ~.125" thick.
https://blp.com/cart/index.php?main_pag ... ts_id=1052 These are .031" thick
http://blp.com/cart/index.php?main_page ... ts_id=1053 These are .047" thick
https://blp.com/cart/index.php?main_pag ... ts_id=1054 These are .062" thick
https://blp.com/cart/index.php?main_pag ... ts_id=1055 These are .095" thick
http://blp.com/cart/index.php?main_page ... ts_id=1056 These are .125" thick

Learn something every day. I did not know that. Thanks for the info.

[In-Tech]

I was on their site a few months ago getting some small parts and spotted these. I saw this post and thought I would pass it along since I "one off'd" the last vortec intake manifold.

[MikeB]

As for gasket thickness, the 350 deck was cut .020" as I recall. Heads haven't been touched.

[novadude]

I like the metal and rubber Fel-pro gaskets that come in the ms98000T kits.

[travis]

I like the metal and rubber Fel-pro gaskets that come in the ms98000T kits.

I just used a set of these on my L31 Suburban a couple weeks ago. Very different than the OEM type plastic and o-ring style gasket (sheet metal with a rubber type material on both sides). Also significantly larger than the stock ports.

[Olds455]

I like the metal and rubber Fel-pro gaskets that come in the ms98000T kits.

I just used a set of these on my L31 Suburban a couple weeks ago. Very different than the OEM type plastic and o-ring style gasket (sheet metal with a rubber type material on both sides). Also significantly larger than the stock ports.

Came to post this. I went back and forth on whether I should go back with stock gaskets or use those new ones considering the stockers made it over 150k miles. I figure if stock went 150k, these should go twice that long.

[CGT]

Gm vortec gaskets are no longer plastic #89017465 is aluminum with embossed oring

[Olds455]

I did not know that. Looks like they've switched to their own "permadry plus" gasket for the entire line of Vortec engines. They're also stock replacements for the V6 Vortec. That wasn't the case just 5 years ago, AFAIK. They weren't available from GM last time I replaced mine in 2014. #89017866

[Olds455]

I've been using Fel-pro 1255 intake gaskets the last couple times. They overhang a bit here and there, but if glued down they don't take much time to trim up. They are .125 thick if you need that thickness for port alignment.

I think GM#89017465 O.E gasket is probably the overall the nicest and best chance of sealing long-term, but I don't like the way they fit personally.

I have had a little trouble sealing up that vortec pattern on the dyno here and there.

I now put a skim coat of rtv sealer around all the intake ports for safe measure. There just isn't any bolts in that area to really push the manifold against the gasket, and the ones on the end are vertical. They just essentially keep the manifold from flying off the engine.

Depending on if your entry is stock in size etc, there is also Felpro 1289 .0625 thick I believe, but larger square opening. If you call Cometic they can burn you some gaskets off of any of the Felpro numbers yet in any thickness you desire pretty much.

I've run into sealing issues on the Vortecs no matter the gasket. The aluminum lower intake likes to corrode around the water ports, making them hard to seal. The fix is usually exactly what you did, which is use RTV to cost the gasket fill all of the imperfections from the corrosion, basically. The intake wasn't corroded, was it?

[CGT]

. Only use Black RTV on the water ports and China Walls.

I've been using Fel-pro 1255 intake gaskets the last couple times. They overhang a bit here and there, but if glued down they don't take much time to trim up. They are .125 thick if you need that thickness for port alignment.

I think GM#89017465 O.E gasket is probably the overall the nicest and best chance of sealing long-term, but I don't like the way they fit personally.

I have had a little trouble sealing up that vortec pattern on the dyno here and there.

I now put a skim coat of rtv sealer around all the intake ports for safe measure. There just isn't any bolts in that area to really push the manifold against the gasket, and the ones on the end are vertical. They just essentially keep the manifold from flying off the engine.

Depending on if your entry is stock in size etc, there is also Felpro 1289 .0625 thick I believe, but larger square opening. If you call Cometic they can burn you some gaskets off of any of the Felpro numbers yet in any thickness you desire pretty much.

I've run into sealing issues on the Vortecs no matter the gasket. The aluminum lower intake likes to corrode around the water ports, making them hard to seal. The fix is usually exactly what you did, which is use RTV to cost the gasket fill all of the imperfections from the corrosion, basically. The intake wasn't corroded, was it?

Yeah its a manifold bolt pattern now being used for something way outside of its original purpose. It is inferior to the old pattern for what we are doing here. So they can be trickier to seal for sure. Cranking the bolts tighter does nothing, the bolts are not placed in a position to apply pressure to the sealing interface.

Fbird mentions rtv on the coolant ports and end rails only. I've done that plenty, can be fine. I hate using any more rtv than necessary. Im always thinking about possibly reusing the gaskets and easier cleanup. But throwing a vacuum pump on my stuff and beating on it on the dyno is what has led me to glueing the gasket firmly to the head and rtv around the intake ports...pain in the ass to cleanup..thank you carbide scraper

They seem fine with no sealer there. Put a vacuum pump on one on the dyno looking for power and then find out why your not pulling very much vacuum(leak). Hook up a smoke machine to the crankcase and make some observations. If you do, you will likely be putting RTV around the intake ports after that. I know a guy thats chased this around