[Sdpepper]

My 67 has ceramic coated headers and exhaust system that fit super tight to my starter, oil pressure switch and clutch linkage. Wondering if anyone else with a manual tranny has found a better way to create space using particular headers or manifolds? I'm not into racing my car so if creating some distance lessens horsepower, I'm not concerned.
400 ci 4 speed. Thanks in advance for sharing your expertise.

 

[GrandTO]

Ram air manifolds allow access to everything just fine and flow well. IME, you don't really sacrifice much in power vs. headers on stock to mild build. I'll post some ideas about headers if you want to keep what you have.

 

[PontiacJim]

My 67 has ceramic coated headers and exhaust system that fit super tight to my starter, oil pressure switch and clutch linkage. Wondering if anyone else with a manual tranny has found a better way to create space using particular headers or manifolds? I'm not into racing my car so if creating some distance lessens horsepower, I'm not concerned.
400 ci 4 speed. Thanks in advance for sharing your expertise.

Normal - at least you did not have to take the big hammer to them.

Many will go with a mini-starter which is much smaller in size and packs good torque. Many will go with the RobbMc mini-starter ad you can clock the solenoid in different positions and you can clock it downward to get it away from the heat of the tubes. However, this will require some lengthening or replacing of the wiring when you clock the solenoid downward.

Oil pressure switch might be able to use a 90 degree brass elbow instead of coming straight off the filter adapter. Don't over tighten any fitting or oil sender into the housing as it will crack it. They are pipe threads and will tighten up as you snug it down with reasonable force. Do not put teflon tape on anything as the sender has to ground to operate. If you had a mechanical gauge, there is a port on top of the rear block next to the distributor. It uses and allen plug. It can be really hard to remove if it has never been removed and you can mess up/round off the hex edges, so treat it like a stuck bolt with some penetrating oil and some heat cycles - if you go that route. Then use the correct fitting in place of the allen pipe plug and then the oil line end fitting goes into it. I believe a kit will have all the parts needed, but has been many years since I did mine, so memory isn't helping me.

Clutch cross-over shaft as long as it is not hitting and you can get the full pedal throw out of it, you should be good.

 

[Sdpepper]

Ram air manifolds allow access to everything just fine and flow well. IME, you don't really sacrifice much in power vs. headers on stock to mild build. I'll post some ideas about headers if you want to keep what you have.

Thanks, GrandTO! My current header are Hedman's. If there was a different header I could use that would give me some extra room, I would certainly consider it. If my Hedman's are similar to other headers, like Dougs, I would like to hear your ideas on this. Thanks again for responding.

 

[Sdpepper]

Normal - at least you did not have to take the big hammer to them.

Many will go with a mini-starter which is much smaller in size and packs good torque. Many will go with the RobbMc mini-starter ad you can clock the solenoid in different positions and you can clock it downward to get it away from the heat of the tubes. However, this will require some lengthening or replacing of the wiring when you clock the solenoid downward.

Oil pressure switch might be able to use a 90 degree brass elbow instead of coming straight off the filter adapter. Don't over tighten any fitting or oil sender into the housing as it will crack it. They are pipe threads and will tighten up as you snug it down with reasonable force. Do not put teflon tape on anything as the sender has to ground to operate. If you had a mechanical gauge, there is a port on top of the rear block next to the distributor. It uses and allen plug. It can be really hard to remove if it has never been removed and you can mess up/round off the hex edges, so treat it like a stuck bolt with some penetrating oil and some heat cycles - if you go that route. Then use the correct fitting in place of the allen pipe plug and then the oil line end fitting goes into it. I believe a kit will have all the parts needed, but has been many years since I did mine, so memory isn't helping me.

Clutch cross-over shaft as long as it is not hitting and you can get the full pedal throw out of it, you should be good.

Thanks Pontiac Jim. I knew someone with far more expertise than I would have some valuable comments to make. Thank you for being explicit and your thorough response. Much appreciated!!

 

[GrandTO]

Thanks, GrandTO! My current header are Hedman's. If there was a different header I could use that would give me some extra room, I would certainly consider it. If my Hedman's are similar to other headers, like Dougs, I would like to hear your ideas on this. Thanks again for responding.

I have Doug's I don't believe they are that close. I have some photos below. You can decide. I know Hedman's have bee around a long time but my experience is with Hooker headers and Doug's.
When you mentioned starter clearance and O.P. switch led me to believe you had something other than Doug's. I believe I have plenty of clearance for O.P.switch and O.E. style starter. These are 1& 3/4 tubes. Note the clearance issue on pass side upper A arm.
Hope this helps.

 

[JohnnyGTO67]

My 67 has ceramic coated headers and exhaust system that fit super tight to my starter, oil pressure switch and clutch linkage. Wondering if anyone else with a manual tranny has found a better way to create space using particular headers or manifolds? I'm not into racing my car so if creating some distance lessens horsepower, I'm not concerned.
400 ci 4 speed. Thanks in advance for sharing your expertise.

Follow my recent threads for some advice.
The consensus is that Dougs are the way to go if you don't want RAR manifolds

 

[armyadarkness]

My 67, with Dougs Headers and a mini starter, has plenty of room, everywhere. That being said, if I ever remove the headers or engine, I will be replacing the headers with Ram Air manifolds.

They're much cheaper, much easier to install, require much less maint, and the performance is near identical

 

[Sdpepper]

View attachment 163203
View attachment 163202

I have Doug's I don't believe they are that close. I have some photos below. You can decide. I know Hedman's have bee around a long time but my experience is with Hooker headers and Doug's.
When you mentioned starter clearance and O.P. switch led me to believe you had something other than Doug's. I believe I have plenty of clearance for O.P.switch and O.E. style starter. These are 1& 3/4 tubes. Note the clearance issue on pass side upper A arm.
Hope this helps.
View attachment 163205
View attachment 163204

Thanks GrandTO, these pics are very helpful. Your Doug’s certainly do give you more space than my Hedman’s. I’ll check them out. Thanks again.

 

[Sdpepper]

My 67, with Dougs Headers and a mini starter, has plenty of room, everywhere. That being said, if I ever remove the headers or engine, I will be replacing the headers with Ram Air manifolds.

They're much cheaper, much easier to install, require much less maint, and the performance is near identical

Army, do you know if Ram Air sells a model that will bolt to Edelbrock Performer R aluminum heads?

 

[geeteeohguy]

Years ago with a 4 speed '66 GTO, I welded a flag about 2" long to the top leg of the Z bar and drilled a hole in it so the clutch rod from the pedal could connect. This allowed the Z bar to tilt way forward at the top leg, which moved the lower leg rearward, totally clearing the headers. I simply shortened the lower rod and adjusted the upper pedal rod longer. Worked perfectly for the 10 years I had the car. The issue I always had was the bottom leg hitting the down-tube. With the Z bar re-indexed, that bar was 2" further back and hanging in free space.

 

[armyadarkness]

Army, do you know if Ram Air sells a model that will bolt to Edelbrock Performer R aluminum heads?

I don't know the answer to that question but I presume they do. Since the ram air manifolds share the same bolt up pattern as headers

 

[PontiacJim]

I don't know the answer to that question but I presume they do. Since the ram air manifolds share the same bolt up pattern as headers

I think he is asking about "R", the round ports instead of "D" ports. They are not interchangeable and you would have to get the correct RA manifold to match your head's exhaust ports.

This is Round Port manifolds:

https://butlerperformance.com/i-24453522-rar-pontiac-oversized-2-5-outlet-round-port-manifolds-64-79-gm-a-body-gto-70-81-firebird-69-81-grand-prix-mid-late-70s-pair-rar-rm-4-os.html

 

[lust4speed]

Promises of the next batch of round port RA exhaust manifolds have been around for years, but so far they remain unavailable. Used sets come up on eBay but the prices are insane.

Anyone ever wonder whether the very often repeated phrase that cast iron RA manifolds are said to flow almost as good as headers might be incorrect? Ever wonder how a small passage cast RA/HO iron manifold with sharp 90° bends and small passages blended together quickly are said to perform as good as mandrel bent 24"+ long tube headers flowing into a 3" collector?

We have a yearly dyno day with the GTO club that has been going on for several years and we have about 20 members each year that allow their vehicles to be abused on the chassis dyno, and the resulting data presents a definite pattern. In short, stock log manifolds and exhaust really suck, and the RA cast iron manifolds come in about 80% to 85% of long tube headers with similar cams and engine builds. Furthermore, the cast manifold performance drop isn't at just the top of the RPM range, but the loss is consistent throughout the power range. Torque in the 3,000 range also shows a good hit. Somehow people think that the loss is only at the top of the RPM range, but that is not true. What we end up with in creating the performance list after the runs are tabulated is the bottom positions are cars with stock exhaust, the middle of the list are the RA/HO manifolds, and the top cars all have full headers (most of which are Doug's Headers). As far as our 2023 list, #1-13 top spots are header cars, #14-18 are cast iron RA manifolds, and #19-22 are log manifold cars. Not a big sampling, but very consistent results over the years. I have a beautiful set of cast iron RA/HO manifolds on the shelf in my garage, but the Doug's are on my car. My Doug's have been on the engine in the blue car for 13 years and the same set of Remflex header gaskets are still on the engine.

 

[GrandTO]

Generally speaking, nothing is better than headers for making power. But wait...... There's more to it than that.
I found this discussion on the forum and one other video that address the subject directly.

A definitive answer: Headers vs. RA Manifolds

A popular topic for discussion. High Performance Pontiac magazine has conducted and objective comparison of long tube headers, shorty headers, and RA manifolds. Very interesting reading. Headers vs. Manifolds - Huge Aftermarket vs. Stock Exhaust Dyno Test - High Performance Pontiac Magazine Bear

www.gtoforum.com

 

[armyadarkness]

Anyone ever wonder whether the very often repeated phrase that cast iron RA manifolds are said to flow almost as good as headers might be incorrect? Ever wonder how a small passage cast RA/HO iron manifold with sharp 90° bends and small passages blended together quickly are said to perform as good as mandrel bent 24"+ long tube headers flowing into a 3" collector?

Yes, I have wondered about it since I first heard it. It made no sense to me... nevertheless, Im no guru, so I assumed that there was data I hadnt seen.

I definitely dont believe that Shorties arent any better than manny's. Dont know about long tubes, though.

 

[JohnnyGTO67]

Give Paul? a call at Ram Air Resoration. When I spoke with him a year ago he was having trouble receiving manifolds simply because the foundry was not producing, hence why I opted for headers.

 

[GrandTO]

No one seems to have RAR. The standard repro versions have the same supply / manufacturing issue. The only thing I've seen is an old O.E. set on ebay for big money unless you needed something for authentic PHS restoration.

 

[armyadarkness]

The online suppliers of these, still list them... are there inferior ones out there?

 

[JohnnyGTO67]

The online suppliers of these, still list them... are there inferior ones out there?

Not sure if it's vendor propaganda, but I was under the assumption the manifolds supplied through RAR were US made, whereas the overseas brand were lower grade metal. I'm not in the industry so I cannot make that call.

They are all probably made in China or like the new sheet metal, Taiwan.