Intake and Exhaust Gaskets - with or without?

[lizziemeister'sV6]

Hello - assembling a 351E engine freshly overhauled - ordered a gasket set from Olsen's for it. What is your honest opinion on using silicone sealant on the intake gaskets and high heat silicone on the steel exhaust manifolds gaskets? This engine is for my 1965 GMC Suburban which I have owned for going on thirty years and will keep till they pry my cold dead hands off the steering wheel. Thanks, Cliff

[TJ's GMC]

When I put new gaskets on my intake I didn't use silicon. Seems fine without it. I never used silicon on the exhaust manifolds either. lol

[George Bongert]

Greetings fellow club members!

I personally do not recommend using silicone gasket sealant, especially on the intake gaskets. If you use silicone sealant, you will never be able to get away from having the silicone 'oozing' into intake port openings of the intake manifold (as well as the exterior of the intake manifold and it makes a freshly rebuilt engine look like crap). If you must use any kind of sealant on the intake gaskets, use Permatex High Tack gasket spray (areosol can). Permatex has changed the formula on this product (although Heaven knows why) it used to be red in color, but now resembles metallic copper paint. I have used this product on intake gaskets on other engine applications with no adverse results. The high heat silicone for the exhaust gaskets is also not necessary, nor do I recommend using it either.

[lizziemeister'sV6]

Thank You for your opinions on silicone gasket material usage on engine assembly. Just needed to have a little moral support to know everything is done to specs. Nothing is easy when rebuilding these 351's - the E and M being hardest to get gaskets for. A side note to this is I have 2 broken sets of NEW oversize pistons FOR SALE along with misc. engine parts from (2) 351's - if interested please contact me. THANKS AGAIN for your help.