Heya.
I've got an ol poncho 301 sitting around which is destined to run again. No one makes headers for a 301, so I'll be fabbing a set. Are the heads ports the same as a 350 or 400? If so, I could get a kit, and wouldn't have to make the flanges.
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Heya.
I've got an ol poncho 301 sitting around which is destined to run again. No one makes headers for a 301, so I'll be fabbing a set. Are the heads ports the same as a 350 or 400? If so, I could get a kit, and wouldn't have to make the flanges.
Nobody makes anything for this redheaded stepchild. I strongly recommend taking 2 aspirin and laying down with a cool towel on your forehead until the desire to make headers for it goes away.Quote:
Originally Posted by firebird77clone
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Good advice, Tech. I had a light blue 1981 Turbo Trans Am with the 301. It had a "monster" 200 hp and 340 ft. lbs. of torque, THM350C lock-up trans and 3.08 rear axle. It also had the "Jimmy Carter" 85 mph speedometer and those Cylon lights on the hood to show turbo boost. Acceleration wasn't much to write home about, but it had a top end waaay above what that speedo would show. I looked around for ways to increase performance, but gave up. It wasn't worth the trouble. Regardless, it was a very nice looking and well-appointed car.
Well, the next owner can rip it out and convert the perfectly good, rebuilt engine into its rightful place as a boat anchor, but I'm looking forward to custom build the headers, mounts, and exhaust. As for it not being capable of monster performance, I have a sneaking suspicion that it will out perform the four cylinder that's in the car now. When I got the engine it had headers, they were for a 350 or 400, but I had to modify the tubes on the driver's side.
I also had a friend with one of those turbo turds. He was really proud of the "performance" of the thing....seems that he had never had a decent performing car before so, when compared to his previous Toyota, it felt fast. I took him for a ride in an 82 Z/28 (which was a pig in its own right) and he dumped the 301. Unless you are building one to sell/screw someone else, why not put the effort into something with more potential? Many people have tried to make a pig fly, so there is prior history with wringing performance out of this motor.
Torch and bend time!!!
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If I may, allow me please to remind you of a basic tenet of the hobby: keeping these old machines running. The 301 was freshly rebuilt about ten years ago. It had maybe two months of service, before the firebird got hit, and it's been sitting waiting for the last decade or so. That 301 has just as much right to slug out another eighty thousand miles as does a 350.
There is more than a singular standard for performance. The bloody car will go plus ninety now, that 301 is going to make it plain scat. It's not getting built for the strip.
And...
I get to answer the questions:
Why?
You did what?
Actually, after thinking about the idea a bit more, I like it. The "What the bleep" factor alone is worth it. Good luck, and I for one would like to see the progress.Quote:
Originally Posted by firebird77clone
If I am reading things right, the 301 heads had siamesed exhaust ports, rather than the divided ports of the run of the mill Poncho heads, so headers for them will be a fab job from the get go. As to whether they are dogs or not, just like most engines and stuff, opinions differ greatly, but in just making a cursory wander around wikipedia and some other research sites, the 301 is the same bore and stroke as a 302 Chevy, and that engine could be a real screamin' scooter when it was built right. I have always had a soft spot for Pontiacs, even though I let my last one go in 1966; I will watch for your reports and anecdotes of progress on this with some interest.
Edit: Addendum:
I was thinking about this, an often dangerous situation when I do that, and I got to wondering; since all Pontiac engines used the same basic block architecture, and the bore was increased to 4 - 1/16 inches in 1958 for the 370, would a set of later model heads from a 389 fit? If so, you might benefit from perhaps larger valves if the runner volume didn't have an ill effect on air flow. It would also allow you to use a set of headers for a 389 or 400 that fit the chassis at hand; save you from having to custom up a set.
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I've got some pontiac 301 headers if u want them tell me where you live and i will decide on a price.
That's an awesome offer, but I've got it in my head to make them myself, 100%. I've always thought a thicker flange would help with gasket blow out, so I'm going to gouge them out of a piece of 1/4" plate.
Just info, my pre-made flanges that were the base for my lake style pipes are 3/8" thick.Quote:
Originally Posted by firebird77clone
Thanks for the tip, I ought to be able to pick up some thicker plate at the scrap yard
You may be better equipped, but for me buying a pair of CNC laser cut flanges was the only option. Fit is too important to risk, IMO. Stainlessheaders.com listsPontiac, and offers both ss and crs, flat or stubbed.
Use minimum 3/8". If I ever build another set, I'll use 1/2".Quote:
Originally Posted by firebird77clone
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Amen to that, that way after all the warping you can swing it by the machine shop and have them surfaced back to flat and still end up with some thick flanges again!Quote:
Originally Posted by techinspector1
Ok, can do! I have a machining and welding class this semester, it shouldn't take terribly long to knock out a set of flanges.
Say, do any of you techo wizards have a drawing of the ports and bolt holes?
My idea was to template it using metal foil tape.
I did a pattern once by taping a piece of poster board on the block, tapping around the exhaust ports and bolt holes with a brass hammer to embed a pattern, and cutting it out with an Xacto knife.
Why not use an exhaust manifold gasket to lay it out?
Doh! *Smacks head like Homer Simpson* Manifold gaskets are still available on Summit, among other places. CLICK HEREQuote:
Originally Posted by 36 sedan
That's so crazy it just might work
Same way I have done it, thin cardboard, like a cereal box and light taps with a ball of a ball pien hammer, it will actually cut the carboard into a gasket if you go over it enough, gaskets sometimes aren't always exact (Chevy guys know as there where so many port variations) might have to screw it down through two bolt holes to keep it from moving.Quote:
Originally Posted by Henry Rifle
I've always had good luck starting with a gasket, using tape to match the ports on the gasket to the head. Once adjusted its easy to transfer the modified gasket to template whatever you need.
You could put a couple of layers of masking tape across the area and the use a scalpel to cut the holes out. Peel the tape off and stick it to the plate and transfer the pattern. This way the pattern doesn't move around on you.
Make sure the surfaces are really clean of oil and you are good to go.
That's fairly what I had in mind, but with foil duct tape. I'm not sure I can get enough precision with that method, to satisfy my shop instructor.
0142 DIM - Schoenfeld Headers
I usually buy gaskets from Schoenfeld and send them to StainlessHeaders to have custom flanges made from 3/8 stainless
http://www.schoenfeldheaders.com/upl...341879.jpg?853