64 comet/302 long tube headers

The Era of The Square Body Racing Comets
mercbill
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64 comet/302 long tube headers

Post by mercbill »

Okay. the car (64 comet 404) I'm looking at has a 302/c4 auto. It has long tube headers. The owner says they hit the body when the engine torques as the fit is too tight. he recommends installing factor original cast iron exhaust manifolds. This will require new exhaust pipes or a modification to make the existing match up with the OEM.

Or, could I use that trick of putting bolts through the engine mounts? This will require R&R of the engine which has to be a lot of work.

What's the best course of action to take?

Rocket989
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Re: 64 comet/302 long tube headers

Post by Rocket989 »

The most expedient route is to pull out the existing header(s) (depending on whether it's one or both hitting) and whack as needed with a 2-1/2 pound hammer... :)

You can pin the mounts but that's really done to keep 'em from separating. The lock nuts on the through bolts shouldn't be tightened-up or you've largely got solid mounts that'll rattle your teeth! :lol:

I know of only three shelf headers that fit our cars.

-Dougs tri-y's (made for both auto & manual). These typically fit the best and are the only option with 1-5/8 primary tubes
-Hedman 884xx shorties...since these are 'Stang headers the collector angle is wrong & you'll need a competent exhaust shop to cut most of the driver side ball & socket collector off & weld the exhaust pipe directly.
-Sanderson FF6 (IIRC)...these are shorties that apparently fix the driver side collector issue with the Hedmans so should drop in.

I've got experience with the first two, but not the Sandersons (though I've seen 'em installed on a couple Falcons). Depending on the engine mods, I would avoid going back to exhaust manifolds. Any header is going to flow better! :D :D
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poboyjo65
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Re: 64 comet/302 long tube headers

Post by poboyjo65 »

I agree with Rocket.A well placed dent should do the trick. but if it has a bad motor mount that could be letting the motor lean more than normal. I wouldnt think you would have to pull the motor, just raise it up enough to get them out. ( I did) & if it does need new M mounts I would go ahead & pin them. My dougs headers are tight with my set up so I pinned my m mounts to keep it from hitting if the mm ever wore out. I think I do feel more vibes when I flog it but that just adds to the excitement! :lol: :lol: I just drilled thru the mm & the L shaped intermediate mount & put in a big bolt with a locknut. Plenty of room for bolthead & nuts so you dont really have to countersink the pins like other cars. Of course with the MM's out & the engine jacked up a little the headers come out a lot easier if you wanted to do both pins & dents.

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Johno

mercbill
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Re: 64 comet/302 long tube headers

Post by mercbill »

Rocket989 wrote:The most expedient route is to pull out the existing header(s) (depending on whether it's one or both hitting) and whack as needed with a 2-1/2 pound hammer... :)

You can pin the mounts but that's really done to keep 'em from separating. The lock nuts on the through bolts shouldn't be tightened-up or you've largely got solid mounts that'll rattle your teeth! :lol:

I know of only three shelf headers that fit our cars.

-Dougs tri-y's (made for both auto & manual). These typically fit the best and are the only option with 1-5/8 primary tubes
-Hedman 884xx shorties...since these are 'Stang headers the collector angle is wrong & you'll need a competent exhaust shop to cut most of the driver side ball & socket collector off & weld the exhaust pipe directly.
-Sanderson FF6 (IIRC)...these are shorties that apparently fix the driver side collector issue with the Hedmans so should drop in.

I've got experience with the first two, but not the Sandersons (though I've seen 'em installed on a couple Falcons). Depending on the engine mods, I would avoid going back to exhaust manifolds. Any header is going to flow better! :D :D
Rocket, Very nice informative post. Thank you. I have a small sledge hammer that would do the trick.I suspect the passenger side header might be easier to remove of the two. Can this one be removed without lifting the engine? Thanks Bill

mercbill
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Re: 64 comet/302 long tube headers

Post by mercbill »

poboyjo65 wrote:I agree with Rocket.A well placed dent should do the trick. but if it has a bad motor mount that could be letting the motor lean more than normal. I wouldnt think you would have to pull the motor, just raise it up enough to get them out. ( I did) & if it does need new M mounts I would go ahead & pin them. My dougs headers are tight with my set up so I pinned my m mounts to keep it from hitting if the mm ever wore out. I think I do feel more vibes when I flog it but that just adds to the excitement! :lol: :lol: I just drilled thru the mm & the L shaped intermediate mount & put in a big bolt with a locknut. Plenty of room for bolthead & nuts so you dont really have to countersink the pins like other cars. Of course with the MM's out & the engine jacked up a little the headers come out a lot easier if you wanted to do both pins & dents.

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PoBoy,

Lifting the engine would be simpler than removing it completely. The car has been mostly redone. I think the motor mounts should be in good condition. If I buy the car and do all the work to fix this problem I might as well put the bolts in the motor mounts. My drill press has been neglected for quite some time now.

Did I miss anything?

Under the car

Disconnect the driveshaft
Disconnect the exhaust pipes
Disconnect transmission mounts
Disconnect shift linkage/shifter

Engine compartment

Disconnect wiring
Disconnect fuel line
Drain radiator
Disconnect coolant lines

Remove throttle linkage
Remove carb
Install lift plate to intake manifold
Loosen engine mount bolts
Lift engine
Remove header
Remove motor mounts/drill out
Improve header fit with hammer

Reinstall in reverse order

Did I miss anything?
How many hours should this project take?

I used to work on my inboard diesel powered boats a lot. Every project took 3x what I estimated it should take.

Thanks, Bill

Rocket989
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Re: 64 comet/302 long tube headers

Post by Rocket989 »

Bill - Without knowing the header brand/model (and even if so), it's a "maybe"... The pass side is typically easier but there are a lot of variables.

Where are they touching? You may be able to get enough clearance pounding a rod in between to get some air gap (or it may not matter at all where they hit). I keep longer, sacrificial 1/4 and 3/8 extensions with the noses a bit rounded to tap in-between stuff as needed. Since they're hardened steel they work better & last longer than typical round stock.

If you do have to lift the motor, you may as well do as John suggested and replace/pin the mounts.

Lifting with a plate is the easiest route IMHO. You can try leaving the nuts on the mount studs a few threads, but they usually have to come up higher than that...not much but depends on the headers.
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popscomet
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Re: 64 comet/302 long tube headers

Post by popscomet »

I had long tube tri y headers custom built for my 64 with the 5bolt bell housing and the 4spd,and I still had to dimple one.I think that's just a given :!: when dealing with headers :shock: good luck...thanks......POP
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poboyjo65
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Re: 64 comet/302 long tube headers

Post by poboyjo65 »

Yea all headers will be different & including each set from same brand may be slightly different & each car might be different also so you never know until you try. in my case with the dougs try y's the pass side was easier. & both headers were lots easier to remove & install with the motor mounts out of the way. You should only need to raise the engine a little so you may not need to undo anything much to get the MM's off,if you plan to pin them, so you might see if they will come off first. I think once I jacked up the engine with a floorjack & pc of wood under the oilpan. I've done that plenty of times on other cars. you could do one side at a time if needed. & dont worry about loosing any power from a dented header, these guys made a tad MORE power by denting headers :shock:
https://www.youtube.com/watch?v=azPKIjxmmdU

Good luck!
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mercbill
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Re: 64 comet/302 long tube headers

Post by mercbill »

Rocket989 wrote:Bill - Without knowing the header brand/model (and even if so), it's a "maybe"... The pass side is typically easier but there are a lot of variables.

Where are they touching? You may be able to get enough clearance pounding a rod in between to get some air gap (or it may not matter at all where they hit). I keep longer, sacrificial 1/4 and 3/8 extensions with the noses a bit rounded to tap in-between stuff as needed. Since they're hardened steel they work better & last longer than typical round stock.

If you do have to lift the motor, you may as well do as John suggested and replace/pin the mounts.

Lifting with a plate is the easiest route IMHO. You can try leaving the nuts on the mount studs a few threads, but they usually have to come up higher than that...not much but depends on the headers.
Rocket, I'm not sure where they are touching and don't know what brand. I'll have to see take some photos when I look at the car. The owner is moving and not available on the weekends. The car's about 100 miles away. It's refreshing to know I should be able to fix this without a lot of disassembly. Thanks

mercbill
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Re: 64 comet/302 long tube headers

Post by mercbill »

poboyjo65 wrote:Yea all headers will be different & including each set from same brand may be slightly different & each car might be different also so you never know until you try. in my case with the dougs try y's the pass side was easier. & both headers were lots easier to remove & install with the motor mounts out of the way. You should only need to raise the engine a little so you may not need to undo anything much to get the MM's off,if you plan to pin them, so you might see if they will come off first. I think once I jacked up the engine with a floorjack & pc of wood under the oilpan. I've done that plenty of times on other cars. you could do one side at a time if needed. & dont worry about loosing any power from a dented header, these guys made a tad MORE power by denting headers :shock:
https://www.youtube.com/watch?v=azPKIjxmmdU

Good luck!
PoBoy, I'm going to start by saying I spent an hour on Youtube watching videos before posting a reply. That channel is addictive.

So, I don't have to worry about damaging the oil pan or causing leaks using a floor jack to lift the engine? That's very beneficial as it means I don't have to rent an engine hoist.

Those guys were hitting the header pipes fairly well. Based on the engine rotation I'd suspect the passenger side would probably hit the frame rail while the driver side might have interference with bolt on stuff. It seems I might be able use Rocket's tip for the passenger side and might have to remove the header for the driver side.

thanks for the link. It might now be my favorite youtube channel.

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Jims65cyclone
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Re: 64 comet/302 long tube headers

Post by Jims65cyclone »

poboyjo65 wrote:I think once I jacked up the engine with a floorjack & pc of wood under the oilpan.
I did that very thing a couple of years ago to change the MM's on my 65. Placed a piece of 2x8 on top of a jack under the oil pan, removed the MM bolts and jacked up the engine just enough to get the old mounts out. The only difference was I did it on a 4-post lift with a sliding cross member between the rails for the jack to sit on. Much easier than laying on my back with the car on jack stands. :wink:
Jim
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poboyjo65
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Re: 64 comet/302 long tube headers

Post by poboyjo65 »

Yea I like those videos comparing things with a dyno. There is one for fans that's pretty cool from those same guys.
I would not say you dont have to worry, but use common sense when jacking.use wood big enough to spread the load ,choke up on the jack handle so you dont have so much leverage & if you feel it get harder Stop & find out why. If it hangs on something it will bend the pan if you keep on jacking. & if you do one side at a time it wont have room to fall down..
Maybe If you can get the MM out just by getting the weight off ,then the header may slip out easy. loosen the trans mount so it can pivot a little. So you may not need to jack it up more than an inch or so.
& if it gets you mad walk away for a while & take a break! :D

Here is another video if you get all wound up & mad at it. :lol:
https://www.youtube.com/watch?v=ggeab0l ... geab0lKz2c
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mercbill
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Re: 64 comet/302 long tube headers

Post by mercbill »

Jims65cyclone wrote:
poboyjo65 wrote:I think once I jacked up the engine with a floorjack & pc of wood under the oilpan.
I did that very thing a couple of years ago to change the MM's on my 65. Placed a piece of 2x8 on top of a jack under the oil pan, removed the MM bolts and jacked up the engine just enough to get the old mounts out. The only difference was I did it on a 4-post lift with a sliding cross member between the rails for the jack to sit on. Much easier than laying on my back with the car on jack stands. :wink:
Jim
That's the best way to do it. I wish I had a garage with a lift in it.

mercbill
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Re: 64 comet/302 long tube headers

Post by mercbill »

poboyjo65 wrote:Yea I like those videos comparing things with a dyno. There is one for fans that's pretty cool from those same guys.
I would not say you dont have to worry, but use common sense when jacking.use wood big enough to spread the load ,choke up on the jack handle so you dont have so much leverage & if you feel it get harder Stop & find out why. If it hangs on something it will bend the pan if you keep on jacking. & if you do one side at a time it wont have room to fall down..
Maybe If you can get the MM out just by getting the weight off ,then the header may slip out easy. loosen the trans mount so it can pivot a little. So you may not need to jack it up more than an inch or so.
& if it gets you mad walk away for a while & take a break! :D

Here is another video if you get all wound up & mad at it. :lol:
https://www.youtube.com/watch?v=ggeab0l ... geab0lKz2c
those are more good tips. I'm careful and patient. Back when I had boats, I had to replace a set of exhaust manifolds on a 302. most of the bolt heads were rusted to the cast iron manifolds They were below deck height so access was poor. I stripped the heads on them before finding out they were rusted to the manifold. I bought my very first dremel moto too with extension. I had to cut the tops off all those bolts to get the manifolds off. It took several weekends. Once the bolt heads were off, the rest of the bolt spun out easily.

I also have a chain hoist I could use to lift the engine but it'll require taking the hood and carb off and using the carb lift point. I used it to set and align 1150 pound diesel engines in my last boat.

I'm a big fan of the Allman brothers music. Great song. Thanks to everyone for the support and advice.

popscomet
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Re: 64 comet/302 long tube headers

Post by popscomet »

the way OL POP sees it ,,if you can change out a 1200 lb diesel motor in a boat,,you should be able to work on a set of headers on a comet.....so why all the questions ???....this ain't brain repair !! your jacking up a motor,,,common sense comes into play some where////don't mean to upset you ,,,but give us a break....if you can work on a boat....you can work on a comet :shock: :shock: :? :? :? :? ...of course this is all POP's opinion.....pop
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