Thread: 302 cyl head print (needed!)

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Have any of you heared of transfer screws. Transfer screws are hardened set screws with a point. Thread them into the tapped hole with a special tool place the header flange stock over the bolt pattern. Hit the flange with a hammer. You now have the desired bolt pattern. Drill a starter hole for the port then die grind to to match the cylinder head. The problem with this type of precision is that the dimensions change with temperature. Headers can get cherry red and the cylinder head doesen't get nearly that hot. The cylinder head has greater mass than the headers so they change temperature at different rates. The holes in the exhaust manifold or header flange are large to allow for this. If you are in school and have access to fancy tools ask your instructor about an inspection machine or ask how to take measurements using your milling machine.

Originally Posted by Louey

The name they go by is Transfer punch set. They vary in cost from 10 bucks up to almost 200. Depending on what you plan to use them on. I've used these for years in many things.
Most of the time, on header flanges, they only have one hole that is to the right size, called a locator hole. The rest are bigger to allow for mis-aligned holes, and heat expansion.
Example of transfer punch set.
http://www.harborfreight.com/28-piec...-set-3577.html

i still lay out two holes.then i have used long body pointed set screws for threaded transfer . laying out the hole and finding center some times work s better then just a transfer punch what bears on this is how thick the pattern is

herlong must of never used a set of header flange s from any u weld kits ? well most are junk .. i made my own up out of 3/8 cold roll and used the header gasket for lay out i made many as i did build headers for some time. lay them up on the mill stack two sets up at i time use a hole saw and ruffing mill to do the job . i buy them now for the sbc as a guy i know cuts them on a cnc .there are now many that sell just flanges so not a money maker

Any more just the cost of metal to do one set will be more $ than purchasing a set from Stainless Headers in MN. Now if a person was going to do 500 sets-----

I use the 3/8" flanges that Speedway and many other companies sell with their header kits.... Never had to do more then elongate a hole or two. Building headers is labor intensive enough without wasting a bunch of time building flanges!!!! I'm with Jerry, maybe if I needed 500 sets, but for only a 1 time deal???? On any unique engines or unusual tube requirement, I just get the appropriate header gasket and take it out to my pal Brian at Laser Cut.... Times gotta be worth something, or at least better spent on the rest of the car???

Of course you could do 8 individual ports--I always cut them anyway

Louey--the transfer screws are sort of like set screws with a hardened point that points out and is installed with the tool holder--they come 5 or 6 to a size inside the holder, I will try to find an example

Check McMaster
part number 3385a19

Originally Posted by jerry clayton

Of course you could do 8 individual ports--I always cut them anyway

Louey--the transfer screws are sort of like set screws with a hardened point that points out and is installed with the tool holder--they come 5 or 6 to a size inside the holder, I will try to find an example

Check McMaster
part number 3385a19

Transfer screws have threads to go in a threaded hole. Transfer punches are not threaded. Transfer punches would be used if you were using the exhaust manifold to get the header flange bolt pattern.

yep and all the big tube stuff can be slip fit so the flanges sometimes needs to be cut .when i made the flanges up i could cut them only were i needed keep getting things mixed up. if for a slip fit tube. if a 2.1/4 or 2.3/8 tube and all needed to be slip fit the i cut up the flange more .i try not to make any headers with to may slip fits and welded header collectors tig weld a L and R on them and welded the tabs on the collector on only one way things get mixed up after there all apart. learn that the hard way after a guy beat the hell out of a set i did a long time ago chevy ll with a bbc in it with 2 1/8 he called me after beating the $hit out of them to make them fit after i bent tabs back they fit

OK----put 2 bplts--3/8 with sesctoion of untreaded shank into the two bolt holes---take a starret ruler ( 1/2 wide) put across the two bolt shanks, measure to top of port----measure to bottom of port---play with the constant values in this game ----3/8, .375, 1/2, .500, .1875, .6875, .875----a little addition, a little subtration, a little of this, that, etc----if you can't fiqure out the diminsions--------

Originally Posted by jerry clayton

OK----put 2 bplts--3/8 with sesctoion of untreaded shank into the two bolt holes---take a starret ruler ( 1/2 wide) put across the two bolt shanks, measure to top of port----measure to bottom of port---play with the constant values in this game ----3/8, .375, 1/2, .500, .1875, .6875, .875----a little addition, a little subtration, a little of this, that, etc----if you can't fiqure out the diminsions--------

Yep, you can scale it either graphically or by Jerry's method, but the point is the kid is asking for a Ford drawing that shows that dimension, thinking that if the dimension shown on some design drawing is used the world is in balance. Not saying it cannot be figured out, just that it cannot be calculated. Look back at post #23 of this thread and you and I are on the same page, Jerry. He did not like it then, either

And the whole thing of making your own header flanges is to end up with a hole size that will exactly take a tube size--ie--the distance around the port hole in the flange equals the od circumferce of the tube for the header----like 2 x Pi ==6.28----adjust the location of the port so as to reduct reversion, etc

Sorry fellas, i'v been busy with other car stuff, (blown head gaskets in a 3.8l (88) thunderbird + getting parts for trans) and havnt had time to do much header work.

But here is the wood milled flange i made for a prototype. Its not the best picture because its just off my phone, and i was at a weird angle so the ports LOOK like they dont line up evenly, but i asure you that there is an even amount of port on all sides inside the flange.

i also changed the orginal design alittle. I got rid of the chamfer around the edges, and then i also changed the bottom out side corners to not interfere with the cyl head bolt, as it is in the picture. I'l hopfuly get a final product here soon and post pictures

you may have to make room for the lower row of head bolts / studs .that is why i made alot of my flanges

you need to raise the plate so the overlap is at the top instead of bottom to stop reversion

(and for bolt /plug clearance?

Ya i know, i changed the design for the head bolts in the way.
plugs fit in fine. i gota get a better picture up here soon.

what overlap are you talking about?
The school is closed for thanksgiving break so i'l have to start the metal work next monday.