hey all, i have a 350 chevy small block that i am putting back together, (i'm in a learning process) the question i have for you is when installing headers what are the pro's and cons of gaskets. a few people roll their eyes at me when i ask this question. some say do as the company you buy the headers from tell you, some say always use gaskets, and some say never use gaskets on headers. i would like to know any of your thoughts, why one way would be better than the other. or is it just a matter of opinion? the headers will be block huggers that will end up in my 1953 chevy (in case additional application info is needed) i appreciate any input thanks again andy
More important than the gasket is whether or not the flange on the headers is flat. Get a really big file and make sure of it. I used to run gaskets, but they just wouldn't last. I haven't been able to find header gaskets with a flame ring, and since there isn't any asbestos in them anymore that means the fibres get burned. Now I just use a light smear of RTV and no gasket. But the bolts do keep coming loose.
I run the copper header gaskets with the header bolts that have the locking tab on the ends that keep them from backing out. No leaks...in 3 years!
I haven't used header gaskets in 12 years, just plain ole RTV. I don't even use the high temp stuff. No problems.
I won't say YOU HAVE TO USE THEM, but I always have. Never had issues either. Honestly I have never even thought of not using them, but only because no one ever said to me they dont use them. Who knows, I might try it.
same thing here, I've had RTV silicone, no gasket, on the headers on my '56 for years, I really don't even remember when I had them off last. ditto on filing the flange flat. if you have a square, straight edge or metal/glass table that are near perfect you can check flatness with those. if you're buying new headers, thicker flanges and thicker tubing have had less issues in my experience. For bolts, on mine I think there's just silicone on the bolt threads, maybe I put loc-tite in there...? on other applications I've used the bolts where you slide a tab over the hex head and put an E-clip on over that, locks them with the tab and header primary tube.
Never tried running without gaskets, but heard of it. My strategy is make sure they are flat and mate to the heads properly, as in no tubes so large or small that there is air showing. I've always used regular MrGasket gaskets, but I tighten them carefully, slowly, over and over, through several heat cycles, till they take a set. Bolts stay tight, although I must confess that when I have a hotrod together I'm usually on top it, and routinely check shit like that in addition to valve clearance, timing, dwell, clutch & shifter adjustment, etc.,etc.,,,,,,,,,,
if you are using a cheap header use remflex gaskets. they have a 50% crush rate so they will seal the best even if your header is warped.
AS one who works for a header manufacturer, I have tried everything you guys can think of - silicone, gaskets, hylomar, copper, stainless, etc. On my own stuff, i use good quality gaskets (avoid the hard material ones like the older Mr. Gasket), torque the bolts evenly across the board, starting from the center ports out, and then normally re tighten them after one heat cycle. I generally don't have a problem with blown gaskets or coming loose if i do them this way. Biggest problem I see from customers is they don't tighten them evenly nor to the proper torque. The reality is though, headers see alot of expansion and contraction from heat cycling and gaskets don't last for ever in this environment. Just part of hot rodding life. JMHO
Depends on the header. Some manufacturers recommend gaskets while others don't. I used to use them until I got into a set of Sandersons. They recommended no gasket with a thin layer of Permatex Ultra Black RTV. It's worked well so far....no leaks. -Lee Atomic Radio www.atomicpinup.com
I use copper gaskets, for me the biggest issue is that there is not enought clearance around the bolt to torque it down properly. The header bolts never worked well since you could only get an open end wrench on them and never get them tight, I switched to Stainless allen head bolts and even then have to turn the head dia down to get them to fit right. Small block ford block huggers, the copper has seemed to last the best for me and have lasted over a few years I still get leaks but it won't channel with th ecopper.
one thing i learned on my 327 in my 53 with block huggers..1st time i just used red/orage rtv..worked fine..no problem for one season. 2nd time ( i changed heads and cam) i put on the gaskets..fuckin header bolts started to come loose alot..I have since torqued them down good, and am watching them..but if they continue to back out ..im going to shit can them..or maybe try some loc tite? or just go back to the way sanderson told me to not run gaskets..must be a reason eh?
A good trick also is to split the flange on both sides of the center ports. Will let the headers expand and contract and not pull on the bolts as much.
Headers with a thicker flange helps too. I made headers from scratch for two different cars and I used 3/8" plate to make the flanges. Never had any leaks. If you use headers with 1/4" flanges, and you overtighten them, you probably just warp the flanges and then they'll leak over and over. I had good luck with some new kind of gaskets that are made of a crushable shiny gray graphite stuff. It's soft and crushable and handles high temps. They're kind of fragile until you get them installed though, so don't bend them up.
or run manifolds on your 53. My 54 has stock manifolds on the 350, no worries, sounds great with the exhaust system I have. At times folks ask if it is a big block from the cam/exhaust combo
If I may add my humble .02$ With respects to all, An often overlooked area is the exhaust port flange "depth", i.e., are all the port outlets square to the horizontal centerline of the head. casting shift, (especially in gm, 1 bazillion units) effects head casting also. The same straightedge used to check head "warp" I use on the INTAKE and EXHAUST ports. I have found the ports warped outside to inside because the more accessable fasteners (intake or exhaust ) always seem to get more ....ah ...attention. lol
I learned this years ago from an old friend, now deceased, and have never had a problem with header leaks...run the stock cast iron manifold dimpled gaskets. Buy a good name brand (felpro, etc). Run them about 100 miles and retighten - problem solved. Inexpensive, they don't show, and they don't blow out.
Some good info in this thread, I always thought there was some kinda of voodoo to header stuff, but i guess just having a flat surface, decent gasket and tightening properly along with retightening seems to do the trick. Will have to remember all this for next time. Anthony
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