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As I reassemble my 245 CID block and go to reattach the manifolds, I am curious if there is a need to seal the gaskets, especially the intake, with any high-heat sealant???
I have put a straight edge across the machined surfaces of both castings and they seem very true. I presume the correct procedure is to reattach them with the manifold-to-manifold bolts loose, snug up the head attachment surfaces and then tighten the casting attachment bolts. When I disassembled the motor, I did notice what looked like black silicone on the intake gaskets. I realize that a perfect seal is crucial, particularly with the intake, and am wondering what convention dictates here??? Maybe just the new gaskets properly torqued are sufficient?? Thanks to any willing to share.

You don't seal intake, exhaust or carburetor gaskets. There's no need due to the gasket design but also the heat would make short work of any sealer, especially on the exhaust manifold.

Thank you Don... I agree that the exhaust manifold would 'bake' most sealing products, even the high-heat stuff, but not having the intake ports sucking any air is so critical and I thought maybe there was some product that could be used to 'assist' the gasket seal; like I said - there was something on the gaskets/manifold, when I took it apart. That being said, there have been so many things that were done wrong by the 'last guy' that I don't trust anything I see as being 'correct'. I mean, the guy put the wrong size rings in the motor and then put spacers in behind them to try and get them to seat!!! No wonder I had all the stalling and powering out issues. But that is why I ask the questions and at least when I get answers here, I feel like I am getting the 'straight goods'. Thanks for the advice.

My knowledge is rusty but I'm always happy to help when I can! I have more difficulty staying logged in long enough to post a reply than I do in actually writing it.

Based on what you said here in different postings on these pages and what you've told me by direct email, it is real wonder that it ran at all and I can't imagine any mechanic no matter how bad doing the things you described. Even when I rebuilt my first 245 for my 1940 110 at 17 years of age I knew better. In fact, it ran so smoothly that when I was once pulled over by the police to look at it, the officer had one foot on the running board and an arm on the open door and asked how it ran. I said, it IS running! I hope yours is as good, if not better, after all this recent work and I expect it will be.

Probably too late, but the manifold gaskets for my 356 came in two flavors. I was advised to request the original metal ones that have about a 1/4" edge that fits inside the manifold ports. I was able to exchange the 'plain flat' ones for a refund when I purchased the metal ones. From Olson's Gaskets in Washington. But I'm not sure if this style was original for a '39 6 245.

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Thanks Joe, appreciate you taking the time to post on the subject. Not too late as I am in the throes of Canadian winter up here and will not put the engine back in until spring as the shop I have the car in is not heated. I have the rebuilt engine in in my very small heated shop at my place and have been detailing and painting all the engine components, readying everything for the 'big project' once the snow melts. The gaskets that came with the rebuild kit are of a smooth, grey material that appears to have some kind of metal inserted into the plies. I will contact Olsen gasket and see what they have available for the 245-6. Also, quite a while back, I had seen an original Packard set of exhaust gaskets on Ebay and had bought them for eventual use. I'll check and see what type they are. Thanks again for the info. Chris

Keep in mind that the exhaust manifold gets much hotter than the intake manifold and engine block and thus expands more than the block it's mounted to. If used, a sealant will try to resist that movement which can lead to early gasket failure most especially with the composite gasket type.

Okay Dave, thanks - that makes sense. I did go on the Olsen Gasket Co. site and they show the rebuild kits for the 245-6 and the exhaust/intake set of gaskets look identical to what I have, left over from the kit the machine shop that rebuilt my engine, passed along to me. To be clear, the gaskets (3 of them) cover the 9 holes in the head and the material they are made of is the same for both intake and exhaust. I kind of expected metal compression ring style round gaskets for the high heat holes and a more conventional gasket stock for the intake. That they are all the same would kind of indicate to me that they are either overkill for the intake or 'underkill' for the exhaust, yes/no????? Regardless, I'm sure both sets get pretty darn hot so I hope it is a worthy, heat resistant product from which they are stamped.

The flat metal-covered gaskets, or sometimes a thin metal core with an asbestos-like outside material, are what I've akways used and never had one leak. You never use sealer on exhaust or intake manifolds.

I am experiencing an intermittent loud whistle from the intake manifold area just below the base of my carburetor, between carburetor and engine block side. It's very difficult to see back there, no room even for a mirror. How is it possible to get a whistle from an intake manifold leak?