I did search to no avail. I need to ding one tube of my nickel coated Thorley header tubes for sparkplug clearance. Is there any special trick to doing this?
Thanks!

hammer-time

I'm sure there's a preferred way to do it properly but I'd start by marking the tube you need to 'dent' with a marker at the spot you intend to shape.
Take the header off and secure it with that spot facing up or at a comfortable angle and supported below the marked area. Wrap a 5/8" or 3/4" socket with thick cardboard like what comes on the back of a big pad of paper and tape it on. Tap it with just enough pressure to dimple the tube little by little, until you create the desired clearance. I might even put a thin towel over the spot to help prevent marking the tubes coating even more.

I did mine like HiwayJoe said, with a slightly different technique. I used a 9/16" deep impact socket, and I wrapped the header tube with a double layer of masking tape - nothing on the socket. I was surprised how hard I had to hit it!! but it worked great and didn't mark the ceramic coating.

I still don't get it ??? We buy a $400 (just guessing at the price) set of headers, then they dont fit and what do we do...we DENT them ??????? I would be sending them right back and telling them to send me a set that worked !!!!!!!!! The more you guys put up with this crap, they less incentive anyone has to make good quality parts that fit the first time. SEND THEM BACK !

Bill....

Are you saying that if he had Thorley send him an exact replacement set that they'd fit?? I would think that header manufacturers, as well as most any other auto part, would be building their stuff in jigs. Wouldn't they all come out needing to be dimpled?
Or should he request a different style\part number until a set fits, or change brands altogether?

With sheet metal, it's a crap shoot. With headers, I guess you'd have to have some custom work done before shipping.

i "dinged" mine with a ball peen hammer. they weren't coated, but i would think a thin piece of rubber or what have you would protect the coating. and, i do totally agree with bill, if you throw a set of headers on and they are so totally whacked they hit the floor or whatever, i would immediately send them back, and buy elsewhere. but, these headers are cheap in comparison, (even a 400$ set) to totally custom headers, or say if you bought them right from gm, and some slight (note now i said slight) massageing around pitman arms, steering boxes, etc, should be almost expected. in fact, my hooker supercomps came with instructions that say basically that very thing, and "some slight dimpling may be needed for some applications", and i'm o.k with that. remember, once you deviate from stock, expect some "engineering" on the fly, imo. my hookers needed slight dimpling at the pitman arm, and other than that fit perfectly. i'm definately the first person to get p/o'ed at shoddy craftsmanship, but some aftermaket parts should be expected to require slight "custom" fitting, imo. just my .02 graemlins/beers.gif

BiiK-

The fact of the matter in my case is that the FB head locates the exhaust port differently on the cylinder head than stock, and the only header I've found "specifically" made for my engine is shorty header, which I don't want. Also throw into the mix that Chev made three different height motor mounts for the small block cars you can expect some variations in fit. So I made do. If I'd sent headers back because they don't fit perfectly, my car would still be up on stands instead of on the road. I consider it to be a part of "car crafting" and I don't mind it at all. Now if my intake manifold or cylinder heads didn't fit, that would be a different story....

BPOS- I'm in complete agreement with you. I'm on my second set of brand new headers. I've already sent back the Dynomax. I think their are diffences in the exhaust port locations and plug holes with some aftermarket heads. My canfields with angle plugs require a 3/4 inch reach spark plug and I can't find a shorty plug that will work. I'd rather dimple a tube than have to wait to find another set of headers that may/may not work.

BillK- I understand that we pay alot of money for these parts but I don't think that you can expect a manufacturer to be able to handle every single combination of parts out there. For me, dimpling one tube to get at a sparkplug isn't too big of a deal.

Greg, I did not notice the aftermarket heads in your "signature" but......I still have to disagree.....why even waste your money on a set of good flowing heads if you are going to dimple the header and mess up the flow in that exhaust port ?????????? If you want to go fast..do it right. You can get headers made to fit any head out there. Yes you will pay for them, but you paid good money for a set of heads that flow good, why not let them work right ?? Bashing a header tube...not happening here.

BillK - well said. I expect to dimple a $60 set of knock-off headers, but $400 Thorley's :eek:

ps. I did not have to dimple my $120 Hedmans.

pps. sometimes dimpling for plug access is unnecessary. I got an old 1/2" drive 5/8 socket and ground four flat spots on it so we could grab it with a wrench when a regular plug socket would not fit. this was for my friend's 327 with Hooker headers --- didn't like the way they fit either.

Custom made headers cost a fortune if you don't happen to possess the skills to make them yourself. I'll assume not everyone on this board has a limitless supply of money to purchase the perfect-fitting header so we do the best that we can, and we'd rather drive our cars than worry about some infintecimal loss of power due to a dimple in a header tube. I can't imagine that dimpling one header tube for plug clearance is going to have an even marginally noticeable affect on performance unless you have to mash the crap out of the tube. For that matter, many headers come from the manufacturer with clearance dimples in them.

I hate to even say this but here goes...I am considering putting cast iron manifolds back on my restored car. I have tried 3 different high temp header coatings on my Super Comps and they have all bubbled and peeled off. I know I could ship them out to Jet Hot and pay that ridiculous fee to have them coated but after spending all this money for the headers, dimpling them up for the pitman arm and then more money for coating, I am starting to question where the value is. This coating thing has me bummed out enough that I just might just put the GM manifolds back on. The plug changes would be a BREEZE!, the backdrive would fit, the clutch linkage return spring would fit and no more peeling paint. I have a complete restored smog system in a box to install so I have additional incentive. It looks cool IMHO if you have a restored car to have the full enchalada smog package installed. Maybe the extra ponies just aren't worth the hassle to me anymore.

Anyone want a good deal on a slighly used, frequently painted set of Super Comps? graemlins/clonk.gif

-Mark.

I've tried Hedman and Hooker along with cheap brands. Big block and small block, they all don't fit perfect. Seems that the steering box and pitman arm are always the culprits.

i only had to dimple my Hedman Hedders about 1/8" right next to the PS box, but the Dynomax headers that were on there before had a lot of room everywhere, with zero modifications necessary to make them fit. too bad the Jet Hot coating fell off, and i bent the driver's side header on a metal rod sticking out of the ground in a "parking lot" before i could send the headers to Jet Hot for warranty work.
for the record, i have 307 frame and engine mounts. if i'd had 350 mounts, my Hedmans might have cleared, but the HEI probably wouldn't.