# Header fit



## AllenD (Aug 3, 2020)

I have a 71 Lemans Sport convertible 400/400 auto reassembling after a frame off restoration. Had a bad motor mount so replaced them. Trying to install Doug's D590 ceramic coated headers. Right side clears OK but left side hits frame and cannot get sufficient clearance on the left side even if the brake distribution block is relocated.

I would appreciate assistance from anyone that has run into this and has the solution.


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## BearGFR (Aug 25, 2008)

Are you certain that you have the motor mount saddles (the ones that bolt to the cross member) on their correct sides? They're different and not interchangeable side to side. I didn't have a problem on the driver side with my 69, that is not after I relocated the brake distribution block. They would have fit even if I hadn't done that, but would have been so close that it would have been tough to slip a sheet of paper between the block and the header, and I really didn't like the idea of cooking my brake fluid. I also had to seriously "re-bend" the back drive linkage rod in order to keep it and have it functional.

I'm running round ports though...


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## O52 (Jan 27, 2019)

There are motor mount frame spacers available that will raise the metal frame mount higher off the crossmember giving more clearance. This is primarily for those who have oil pan clearance problems due to frame sag. 
I think a member of the PY forums sells them.


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## steve491 (Nov 20, 2019)

I tried headers on my 67 and the passenger side fit fine but the driver side hit the brake distribution block. It cleared the starter, steering shaft, and Z-bar. My deal breaker was the ground clearance. I didn't want to hit a dip or speed bump and damage the tubes and more importantly the collector flange. HO/RAM AIR manifolds are the way to go.


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## Mine'sa66 (Oct 30, 2019)

When I read the title "Header Fit"
I just want to write
"Hardly Ever".


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## RMTZ67 (Mar 12, 2011)

I had bought headers even tho I read of all the issues. But had bought it for cosmetic purposes as well as function..but as soon as I realized you can hardly even see them because of the slant on the heads, I sold them and ordered RA Manifolds and avoided all these issues. Got the ceramic coated and 2.5 downpipes and easily realized that was one of my best decisions. A little pricey but well worth it... minus the aggravations.


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## Jared (Apr 19, 2013)

I'm currently tossing the header vs. RA manifolds debate around as well. The cost is almost a wash but the fitment issues have me leaning towards the RA manifolds. I'm honestly thinking that the little power left on the table using the manifolds is probably worth it.


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## Mine'sa66 (Oct 30, 2019)

Jared said:


> I'm currently tossing the header vs. RA manifolds debate around as well. The cost is almost a wash but the fitment issues have me leaning towards the RA manifolds. I'm honestly thinking that the little power left on the table using the manifolds is probably worth it.


Most will tell you that unless you're trying to make really big HP, there is no real loss with RA manifolds.


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## Jimbullets (Aug 9, 2020)

Jared said:


> I'm currently tossing the header vs. RA manifolds debate around as well. The cost is almost a wash but the fitment issues have me leaning towards the RA manifolds. I'm honestly thinking that the little power left on the table using the manifolds is probably worth it.


Have You tried the Three Tube Hedders ,I am pleased with them ,so much easier and work well .


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## Jared (Apr 19, 2013)

Jimbullets said:


> Have You tried the Three Tube Hedders ,I am pleased with them ,so much easier and work well .


I had headers on one other car and they were a headache. Those were on an 80's Camaro and they fit pretty good on that car. I fought constant gasket leaks which turned me off on headers. That experience coupled with the fitment issues folks seem to have on the GTO/LeMans chassis makes me very hesitant especially with how well the RA manifolds are supposed to flow.


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## O52 (Jan 27, 2019)

And there's different versions (Outlet size) of the repo RA manifolds. IMHO unless you race the car or like the bling factor, there's no reason to use headers when RA manifolds are available.


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## Jimbullets (Aug 9, 2020)

Pontiac 4 tube Hedders are really hard to fit , I have used three tube Hedders on my GTO'S since 1977 they have better fit and hardly ever leak after bolted up . 4 tubes always hard to work around and ground clearance was bottom out a few times on the street .


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## Jimbullets (Aug 9, 2020)

O52 said:


> And there's different versions (Outlet size) of the repo RA manifolds. IMHO unless you race the car or like the bling factor, there's no reason to use headers when RA manifolds are available.


How much horsepower loss with manifolds ?


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## Jimbullets (Aug 9, 2020)

Where are manifolds you are looking at , I would like to see them , I have used Hedders with really happy with on three tubes , and yes I do like a little racing .


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## Old Man Taylor (May 9, 2011)

Jimbullets said:


> How much horsepower loss with manifolds ?


It depends on the cam you are running. My guess is that with a tame cam there might be no loss at all. When I ran a large cam I ran 12.59 at 110 with the RA manifolds, and 12.20 at 114 with good 4 tube headers.


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## Jimbullets (Aug 9, 2020)

I'm running a 4 speed,GTO Convertible , I don't remember the cam size off hand but it was a isky hydraulic and , I have a couple more GTO'S too build ,I will go a more traditional cam for the 69 Judge resto ,53,000 orginal miles all orginal paint depends if I find a buyer or just build two Engine's , really want a IA two block I think for Convertible 68 .


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## Old Man Taylor (May 9, 2011)

I have an IAII block in my racecar with Edelbrock heads. Mine is 505 ci. It has a 1/8" deeper pan rail to allow for the registered main caps. That means your pan will sit 1/8" lower. The pan actually hit the steering arm in my '64 Tempest.


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## Jimbullets (Aug 9, 2020)

What about on 1968 GTO Convertible with A/C and power steering ,power brakes ,any Problems ?


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## Old Man Taylor (May 9, 2011)

Just check how close your pan is to your steering arm. You will also have to keep this in mind if you choose an aftermarket pan.


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## Jared (Apr 19, 2013)

Jimbullets said:


> Where are manifolds you are looking at , I would like to see them , I have used Hedders with really happy with on three tubes , and yes I do like a little racing .


These are the ones I'm considering. 






Pontiac Ram Air Manifolds


Pair LH and RH Ram Air D-port manifolds (shown with gray ceramic coating) <P> Fits 68-72 GM a-body with d-port heads. Also fits 70 1/2 - 81 f-body. ***For those using cylinder without end bolt holes (i.e. #7K3, 7M5, etc) we have a fix that doesn't requ




www.ramairrestoration.com





These have a 2.5 inch flange instead of the 2.25 that the stock ones were. I'm in the process of building a 461 and like the larger than stock size on these. I don't plan on doing any racing so I doubt there would be much difference between these and headers for me.


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## michaelfind (Dec 14, 2018)

Jared said:


> These are the ones I'm considering.
> 
> 
> 
> ...


I am very pleased with the ram air restorations oversized RA manifolds on my 467 stroker with 6x heads.


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## Jared (Apr 19, 2013)

michaelfind said:


> I am very pleased with the ram air restorations oversized RA manifolds on my 467 stroker with 6x heads.


Great input. Sounds like your set up is very similar to what I am putting together.


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## driftercb (May 15, 2020)

AllenD said:


> I have a 71 Lemans Sport convertible 400/400 auto reassembling after a frame off restoration. Had a bad motor mount so replaced them. Trying to install Doug's D590 ceramic coated headers. Right side clears OK but left side hits frame and cannot get sufficient clearance on the left side even if the brake distribution block is relocated.
> 
> I would appreciate assistance from anyone that has run into this and has the solution.


I had the same problems with Dougs headers.


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## michaelfind (Dec 14, 2018)

Jared said:


> Great input. Sounds like your set up is very similar to what I am putting together.


I forgot to mention that I did also order the matching mandrel bent down pipes to keep the flow as good as possible. It sounds good and seems to flow very well. This set up is much stronger than the 400 with 4 tube headers I was running. I admit that it's hardly a fair comparison (balanced stroker 467 versus the very tired 400 that I replaced), but that is my frame of reference for now. I certainly don't think I'm leaving much torque on the table by not going with headers. And I don't tighten up and cringe each time I drive over a speed bump waiting for the horrible crunch on the headers pipes!


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## Jared (Apr 19, 2013)

michaelfind said:


> I forgot to mention that I did also order the matching mandrel bent down pipes to keep the flow as good as possible. It sounds good and seems to flow very well. This set up is much stronger than the 400 with 4 tube headers I was running. I admit that it's hardly a fair comparison (balanced stroker 467 versus the very tired 400 that I replaced), but that is my frame of reference for now. I certainly don't think I'm leaving much torque on the table by not going with headers. And I don't tighten up and cringe each time I drive over a speed bump waiting for the horrible crunch on the headers pipes!


Same as I was looking to do. I just installed a Pypes 2.5" system with the straight through mufflers a month before my 400 grenaded. It looks like the longer down pipes should match right up with the front of the x pipe at the cross member. Thanks for the insight on this.


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## michaelfind (Dec 14, 2018)

Jared said:


> Same as I was looking to do. I just installed a Pypes 2.5" system with the straight through mufflers a month before my 400 grenaded. It looks like the longer down pipes should match right up with the front of the x pipe at the cross member. Thanks for the insight on this.


And it they don't quite reach, you can fill in the gap, as I did, with some nice cut outs for those days you want to go to the track and be very loud.


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## AllenD (Aug 3, 2020)

AllenD said:


> I have a 71 Lemans Sport convertible 400/400 auto reassembling after a frame off restoration. Had a bad motor mount so replaced them. Trying to install Doug's D590 ceramic coated headers. Right side clears OK but left side hits frame and cannot get sufficient clearance on the left side even if the brake distribution block is relocated.
> 
> I would appreciate assistance from anyone that has run into this and has the solution.


Quick update on this. I followed the advice and purchased the Ram Air Restorations ceramic coated versions and stainless exhaust. no more clearance issue but have a set of Doug's Headers that I need to sell.


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## Jared (Apr 19, 2013)

AllenD said:


> Quick update on this. I followed the advice and purchased the Ram Air Restorations ceramic coated versions and stainless exhaust. no more clearance issue but have a set of Doug's Headers that I need to sell.


Thanks for the update. I haven't ordered mine yet but will be soon. I was waiting until the heads were ready and was told recently that they should be ready within the next few weeks.


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