Manifolds to Headers??

[Big Secz 26]

With my motor getting rebuilt I was going to purchase a new set of exhaust manifolds since mine are like extremely rusty and I think original to the car. I started looking online and finding a set of manifolds for a '70 302 seems more challenging than I thought. So I started looking at a set of shorty headers. I was thinking of these:

http://www.summitracing.com/parts/HED-88408/?rtype=10

 

My question is how difficult and expensive do you all think it will be to modify my 2" exhaust to fit these headers? And what are the chances that these will fit without having to do any modifications?

[krewlstang 10]

You will definetly have to mod the exhaust by adding the collectors to the pipes, but I'm not sure how far off the manifold exits are as opposed to the headers exit.

[69RavenConv 286]

It's funny you should ask this question now because I was wandering around Summit's showroom last weekend pondering the same thing. I have the OEM manifolds on the car but I have a set of used long tubes hanging in my shop wall. In fact, Summit had a nice set of ceramic coated Doug's for SB Ford on the 'scratch and dent' table that I almost bought.

 

Mating to your 2" pipes shouldn't be an issue. You'll need an appropriate H-pipe (or X-pipe), and appropriate reducers. Reducers are easy, they come in all sizes. H-pipe, not so much. If you bought your exhaust as a kit, often the vendor will offer both a "stock" option and a "header" option and you can go back and buy the "header" version. If not, you may have to get a muffler shop to fabricate one.

[krewlstang 10]

It's funny you should ask this question now because I was wandering around Summit's showroom last weekend pondering the same thing. I have the OEM manifolds on the car but I have a set of used long tubes hanging in my shop wall. In fact, Summit had a nice set of ceramic coated Doug's for SB Ford on the 'scratch and dent' table that I almost bought.

 

Mating to your 2" pipes shouldn't be an issue. You'll need an appropriate H-pipe (or X-pipe), and appropriate reducers. Reducers are easy, they come in all sizes. H-pipe, not so much. If you bought your exhaust as a kit, often the vendor will offer both a "stock" option and a "header" option and you can go back and buy the "header" version. If not, you may have to get a muffler shop to fabricate one.

 

Will he even need to change to an x or h pipe or can he just get the reducers and collectors welded onto his current set up? They are a ball and socket type collectors so they should correct for a minor misalignment.

[69RavenConv 286]

Will he even need to change to an x or h pipe or can he just get the reducers and collectors welded onto his current set up?

 

Very good question. With shorties you may not need new pipes. $20 or $30 for the right collectors may do it. I'd call the manufacturer and ask.

[Big Secz 26]

I'd like to stick with shorties for a few reasons, one I figured it would require the least amount of modification to the existing exhaust setup and second I didn't want to take away from ground clearance by going with long tubes. The headers that I linked above actually come with a set of reducers as well.

[maxum96 32]

Shorty headers are an excellent choice for a stock or slightly modified engine.

[Pakrat 1,043]

Just throwing it out there but if the only issue with your current manifolds are that they are rusty then why not just have them sand blasted and repaint? Don't get me wrong I'm a big fan of headers and have long tubes myself but I know you are on a budget and you ended up rebuilding everything else over going new so far so why not here too. You won't have any issues lining things back up and can always upgrade later when it's time for a new exhaust.

[Big Secz 26]

Just throwing it out there but if the only issue with your current manifolds are that they are rusty then why not just have them sand blasted and repaint? Don't get me wrong I'm a big fan of headers and have long tubes myself but I know you are on a budget and you ended up rebuilding everything else over going new so far so why not here too. You won't have any issues lining things back up and can always upgrade later when it's time for a new exhaust.

 

 

Hey Pak,

 

The exhaust isn't even two years old yet. I dropped the motor off today at the shop and spoke to the builder. He suggested shorty headers. He's building it to put out 320-350 hp but he said those are conservative numbers. He's going with a hydraulic roller setup but he said it won't be anything too extreme and I should still have a mild idle. He said I will hear more mechanical noise over a flat tappet and the exhaust note will be different but other than that he said my car won't vibrate excessively from it.

 

So I'll do some shopping now for hearders, the motor should be done in a couple weeks. The trans should be done next week and I'm getting a shift kit and a 1800 stall torque converter. When I'm done it should be a good street car.

[ironhide 10]

I just dropped in a set of Hedman 88406 and have been pleased with them. The hardest part was getting the old long tubes out, the shorties dropped in without a problem. The ceramic coating dropped the pipe temps over 200 degrees, car runs cooler when at idle and I am sure the Pertronix and underhood wiring will last a little longer. I liked the elites with the thicker flange and pipes, but couldn't get a warm feeling on the difference between the "thermal coating" and HTC. The HTC ones are more expensive, but the old headers with thermal paint clearly were causing underhood heat issues that this new set of headers has resolved for me. Plug changes are now a breeze.

 

If I could do it again, I would get the Hedman 88400 and run with them until I had the cash to take them to a local coating shop to get the ceramic coating applied.

[MikeStang 247]

You will love the roller cam, the exhaust not e will be a bit different, its going to be more sharp and crisp sounding....A small roller in a stock headed motor someting in the 230ish @50 on the duration and around .490-.525 on the lift, on a 110-112 Lobe would work great and still have good street manners...and besides if you even upgrade to alum heads you will have a ddecent cam to compliment them.

But then again streetable and doscile is a matter of opinion.

Mike

[Big Secz 26]

I just dropped in a set of Hedman 88406 and have been pleased with them. The hardest part was getting the old long tubes out, the shorties dropped in without a problem. The ceramic coating dropped the pipe temps over 200 degrees, car runs cooler when at idle and I am sure the Pertronix and underhood wiring will last a little longer. I liked the elites with the thicker flange and pipes, but couldn't get a warm feeling on the difference between the "thermal coating" and HTC. The HTC ones are more expensive, but the old headers with thermal paint clearly were causing underhood heat issues that this new set of headers has resolved for me. Plug changes are now a breeze.

 

If I could do it again, I would get the Hedman 88400 and run with them until I had the cash to take them to a local coating shop to get the ceramic coating applied.

 

 

I just ordered a set of 88406 headers. I only hope I don't have any warping issues with the smaller flange. But it's only a difference of an 1/8" so I don't think it'll be an issue.

 

I'm glad to hear that they dropped in so easiliy. I'm just hoping that its going to be a straightforward modification at the muffler shop to fit the exhaust pipes.

[ironhide 10]

The supplied reducer left a bit to be desired, it necked the 2.5" collector down to a 2.25 pipe. I had the shop bell the ends of my new pipes and removed the supplied reducers. You could probably do the installation by yourself, but an extra set of hands did come in handy. Make sure not to break in your new motor with the HCT coated headers. They provide a warning on the Hedman site about it and a leaflet in the box, link here: http://hedman.com/content/pdf6768.pdf.

[69RavenConv 286]

Not to hijack the thread, but are there any shorties that work with a manual tranny z-bar?

[Big Secz 26]

The supplied reducer left a bit to be desired, it necked the 2.5" collector down to a 2.25 pipe. I had the shop bell the ends of my new pipes and removed the supplied reducers. You could probably do the installation by yourself, but an extra set of hands did come in handy. Make sure not to break in your new motor with the HCT coated headers. They provide a warning on the Hedman site about it and a leaflet in the box, link here: http://hedman.com/content/pdf6768.pdf.

 

 

Thanks for the heads-up. The engine builder is going to bench test and tune the motor which will reduce break-in time that I need. But just to be on the safe side I'll run a couple fans under the car like they suggest.

[CandyAppleRed 10]

Not to hijack the thread, but are there any shorties that work with a manual tranny z-bar?

 

I would also be interested in knowing....

[LoneWolf2U 136]

Most shorty headers will work with manual trans clutch linkage, thats why some use them as to not have to fight putting the linkage back in after the headers are installed.

Check Manufacture's app info to be sure.

[69RavenConv 286]

All the shorties in Summit's catalog are automatic only but I'll keep looking (Hedman, Doug's, and Doug Thorley)

[Revrandall 10]

I'm pretty sure the underside of a 70 conv. is the same as a 69 conv. and I had problems with long tube headers on my 69. I had Hooker Competition long tube headers on it for a few years and the drivers side collector was too long which made it necessary for the exhaust pipe to make a fairly sharp bend just after the collector so the exhaust could be routed through the driveshaft tunnel and over the bolt-on coverts reinforcement plate. I put a set of JBA ceramic coated shorty headers on it about ten years ago. Probably lost a little performance but I'll never go back. The change to shorty headers also took away an irritating vibration I had with the long tubes. I've got a very mild 351 in my convert. 375 hp. on an engine dyno..