Exhaust manifold gasket - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Arnulfo · 03-11-2026, 10:32 PM

Seeking opinions on pros and cons of whether or not to use them. From what i understand the factory did not use them. Will be installing a new driver side manifold and head surfaces still in great shape. Thanks for the info

**Steeveedee** · 03-11-2026, 11:52 PM

If they have a lot of pitting, don't bother. I've used a product in the past (VersaChem Exhaust System Joint & Crack Sealer) on a set of exhaust manifolds. Worked a treat.

Arnulfo · 03-12-2026, 02:47 AM

Quote:

Originally Posted by Steeveedee

If they have a lot of pitting, don't bother. I've used a product in the past (VersaChem Exhaust System Joint & Crack Sealer) on a set of exhaust manifolds. Worked a treat.

No pits on the heads nor would i expect any pits on the new manifold. Thinking i may put a thin skin of high temp rtv with no gasket

**425HP409** · 03-14-2026, 04:42 PM

The factory did not use gaskets and the head and manifold surfaces were flat.
A gasket can have problems such as blowing out. they are to make up for not flat surfaces. I have built many engines and never use a gasket. I make sure the head is flat by running a bastard file over the manifold surface and also running the file on the manifold while it is in a vise until you can see the factory broach marks so you know it it flat. It will have high and low spots, make sure that you use the file until it is not leaving any part of the manifold not filled flat.

03-11-2026, 10:32 PM	#1
Arnulfo Registered User Join Date: Aug 2015 Location: Los angeles Posts: 165	Exhaust manifold gasket Seeking opinions on pros and cons of whether or not to use them. From what i understand the factory did not use them. Will be installing a new driver side manifold and head surfaces still in great shape. Thanks for the info

03-11-2026, 11:52 PM	#2
Steeveedee Ram-A-Lam-A-Ding-Dong Join Date: Jan 2013 Location: Simi Valley, CA Posts: 11,899	Re: Exhaust manifold gasket If they have a lot of pitting, don't bother. I've used a product in the past (VersaChem Exhaust System Joint & Crack Sealer) on a set of exhaust manifolds. Worked a treat. __________________ ~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA

03-14-2026, 04:42 PM	#4
425HP409 425hp409 Join Date: Oct 2008 Location: Prosper Texas Posts: 883	Re: Exhaust manifold gasket The factory did not use gaskets and the head and manifold surfaces were flat. A gasket can have problems such as blowing out. they are to make up for not flat surfaces. I have built many engines and never use a gasket. I make sure the head is flat by running a bastard file over the manifold surface and also running the file on the manifold while it is in a vise until you can see the factory broach marks so you know it it flat. It will have high and low spots, make sure that you use the file until it is not leaving any part of the manifold not filled flat. __________________ Charles 68 SWB, Dad bought new, now 396 & factory ac 64 Impala SS, 409 425HP, 4 speed AC 64 Bel Air Wagon, 400 Small Block 57 Bel Air all original 283 w/Factory Air 77 GMC Sprint, 454/425HP 67 Oldsmobile 442, all original



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