[RYU]

I've installed the new 350 Gen I w/ Vortec heads into the 66. All looks ok - engines mounts lined up. Transmission cross member lined up to where it was with the 307/200-4R combo I had in there before. Basically, from a fitment perspective it all bolted in.

I installed Summit (the cheap stuff) Headers and i'm disappointed in them... more on the disappointment on another thread. Anyway, the driver's side header sits about 1-1.5" inches lower than the passenger. It almost seems as if my motor is dipping/tilting lower towards the driver's side. I don't know if these crappy headers are the problem being that one just sits lower or if it's something wrong with my frame or engine mounts. I hope it's not the latter. If you look at how the heads line up and how the air cleaner lines up they all seem to sit parallel to the hood line.

All this is making my new Flowmaster Exhaust system sit funny and i'm spanking my headers on the concrete every so often.

Car is lowered about 1".

Is this normal??? Hope I don't need to pull the block again If it helps i'll take pictures.

 

[kettbo]

The 307 a different (frame ?) mount IIRC.
Am sure more people will chime in here on this.....

 

[RYU]

The 307 a different (frame ?) mount IIRC.
Am sure more people will chime in here on this.....

I thought that also but the mounts themselves look the same for a 350 and a 307. I looked through about 4 cars at Autozone and they all pointed to the same sku#. Now, i can't be sure if where the mounts are welded on the frame are the same.

yes, someone please chime in! thanks!

 

[Keith Tedford]

There was a picture posted here of 307 versus 350-396 frame mounts. The 307 mounts had round holes for the through bolt while the 350 mount had an elongated hole. I got information that the 636 block was 307 and 638 was 327 back in '68. The engine in our el Camino is the 638 block but is a .040" over 307, so I would say the the '638 could be either 327 or 350. The chassis had the 350-396 frame mounts. If any of my information is wrong, let me know as I don't have any history on other than the VIN shows that it at least is a V8 car/truck. A mix up of frame mounts might not have the engine sitting where it should be.

 

[RYU]

Here's an interesting thread that I read. It says the frame mounts are different but only fractionally so. Does this mean I have to weld in new mounts or frame brackets? This speaks more towards front-to-rear engine angle. My problem is side to side alignment.

http://www.chevelles.com/forums/showthread.php?p=1802519

boooo... this is getting complicated.

 

[Tom Mobley]

it's not the mounts, it's the headers themselves. Many brands headers are patterned after some old Hooker design that has the left side hanging further down. Somebody claimed it was originally made that way to clear manual shift linkage or something. The Hookers on my car are like that, the left header is about junked from hitting the ground all the time. The right is untouched. I talked to Hooker and others about this, all got was the standard "Nuttin' wrong with our stuff." I won't be buying from them again. Verification: set the two headers on the floor and bolt them together with two bolts. You'll see instantly.

Lay a level across the valve covers or something.

307 mounts are different, but not in that direction. the stands on the frame are "narrower", if regular mounts are used on the 307 stands there's big gaps on the front and back. The mount will be squeezed together when the the through-bolt is tightened up. Some guys have used spacers to fix the problem, but it's a PITA and the results aren't so hot.

 

[RYU]

it's not the mounts, it's the headers themselves. Many brands headers are patterned after some old Hooker design that has the left side hanging further down. Somebody claimed it was originally made that way to clear manual shift linkage or something. The Hookers on my car are like that, the left header is about junked from hitting the ground all the time. The right is untouched. I talked to Hooker and others about this, all got was the standard "Nuttin' wrong with our stuff." I won't be buying from them again. Verification: set the two headers on the floor and bolt them together with two bolts. You'll see instantly.

Lay a level across the valve covers or something.

307 mounts are different, but not in that direction. the stands on the frame are "narrower", if regular mounts are used on the 307 stands there's big gaps on the front and back. The mount will be squeezed together when the the through-bolt is tightened up. Some guys have used spacers to fix the problem, but it's a PITA and the results aren't so hot.

Tom, very informative. Thank you.

I plan using a level and a straight edge to take some measurements tonight. I also don't have the specific frame mount problem you're talking about it but I could have just not noticed it - which would really scare me. I will check on that tonight as well.

There are so many articles on the web about 307 vs. 350 installs but yours was the first to make sense.

 

[charbilly2001]

I have learned to go over speed bumps VERY carefully. My left side header is at least 1" lower than my right side. Other than that the car is stock height.

 

[RYU]

I have learned to go over speed bumps VERY carefully. My left side header is at least 1" lower than my right side. Other than that the car is stock height.

man... that just isn't right. i don't see any reason why the specs calls for a lower driver side header. unless this was some one-size-fits all with a truck or something.

if all is good with the measurements tonight i might have to buy some better headers. it was such a PITA to install!!!

 

[FerrariTruck]

I had the same issue with the flowtech headers from summit as well. However even though it looks like they are drastically off they will till work fine. You might have to modify your exhaust system, All i had to do was loosen some exchaust clamps and then move the pipes around a lil.

 

[RYU]

Took some pictures. I've readjusted the exhaust and so far the exhaust seems to align itself as it reaches the mufflers so not too worried for now.

It's clearly seen how much lower the driver side header is vs. the passenger side. I'm worried that Summit may have mispackaged the wrong part :sad:

Are your headers "drooping" this badly?

 

[Tom Mobley]

yep, mine are. mine are the cheapie Hookers, Personally, I think these other vendors just copied Hookers design complete with the nasty design flaw. Really can't see any reason why they need to be that way. The left header on my car is trashed, the right one is untouched. My car is a little low though.

http://picasaweb.google.com/tmoble/Chevelle707/photo#5096904707935152866

 

[Racing]

On my Heddman Elites the passenger side header is lower than the drivers side.

 

[highdesert56]

I know the droopy left side hooker header on my 454 '56 bel air (barely) lets me remove the oil filter. I kinda always thought thats why its like that. It's got me plenty scared of speedbumps thats for sure.