Please help with these manifolds!

[68c20lwb]

Will either of these work on my 68 C20 454 4 speed? Which will work better?

http://www.ebay.com/itm/310427159921...84.m1438.l2649

http://www.ebay.com/itm/310406104497...S:1123&vxp=mtr

The key is will they fit with my 4 speed?

[68c20lwb]

nothing?

[OJ1988]

Not sure, On a small block rear dumps won't clear the clutch, not sure about BBC.

[midniteblues]

I'm not sure either but i'm intrested in what you find out I have this set from a 75 chevy truck with a auto (almost like the first set) that I plan on useing when i start doing the bb swap I'm hoping they clear everything.

[RHestand]

I just went out and looked at my 71 C-20 with headers and a 502" crate motor and I would say, IMO, with the rear dumps the clutch bell-crank would not let the head pipe go through.
Of the two sets, I would say the 2nd. set stands the best chance of working but not necessarily with off the shelf head pipes. In other words, you'll probably have to take it to a good quality muffler shop to get your exh. system custom bent and hung.
What I'm trying to say is "I doubt you'll be able to order a prefab exh. kit and expect it to connect up to those manifolds.
Good Luck, Ray

[RHestand]

Originally Posted by midniteblues

I'm not sure either but i'm intrested in what you find out I have this set from a 75 chevy truck with a auto (almost like the first set) that I plan on useing when i start doing the bb swap I'm hoping they clear everything.

IMO, I would say the same to you as to 69c20. Your manifolds will probably work but, you'll probably have to have custom bent pipes.
Ray

[midniteblues]

thank you for checking ,I'm guessing your oe bb 71 ones dump a lil' further forward on the ds
i'm not sure but i cant see why gm would use a differnt ds manifold for manual trans bb than a auto bb truck in 75(I no I no wrong years but these were free) unless the mt crossmember has something too do with it. my ds still has part of the head pipe and it does go straight down for quite a distance but i do know it "was" a custom deul exshaust

[68c20lwb]

i do know i had manifolds that came with my big block, (84 C30 4 speed 2wd) that worked but were cracked terribly on both sides and i guess couldnt be brazed. so now i have just been searching, it is nice, although strange, to know that the manifolds are different. I wanted to purchase the magnaflow kit which requires your own lead pipes anyway. all i need are manifolds

[blackdawn]

if you plan on redoing your exhaust anyway, why not throw a few more bones at it and get headers?

[68c20lwb]

I had headers, 3 different kinds, i was told they were all going to work. None did. So now after having over $1,000 in headers that dont work with my 4 speed I am going with manifolds. Which still seems to pose a problem that I do not understand because the factory did it so why cant I? Anyway, I no longer trust summitracing customer service, at least not more then I trust myself. I think I may order up those vette manifolds and see if they fit right.

[SS Tim]

Don't you think it is unfair to blame summit's tech people for your problem. There have been several threads on this engine issue. Your truck was what a SBC then I6? I6 mounts and stands won't work properly. Stand location is also different. The clutch linkage has been a problematic and you were advised that the big block has specific linkage, mounts and trans. crossmember as well. Is it any suprise that headers designed to fit a stock big block application won't fit your truck? Please sit down and reread all applicable threads. Identify what you have and what you need to do to install the motor correctly. At that point any of you "incorrect" headers should fit.

http://67-72chevytrucks.com/vboard/s...d.php?t=540789

http://67-72chevytrucks.com/vboard/s...d.php?t=540789

Also it has just come to light (to me) that your existing '68 frame has hacked up mount locations.

http://67-72chevytrucks.com/vboard/s...d.php?t=542561

Might want to decide what you want to do here about the frame first.

If you have questions about mounts look at this.

http://67-72chevytrucks.com/vboard/s...d.php?t=437680

[68c20lwb]

The Truck was a small block originally yes. I then went to a BBC. The BBC is in the truck as the factory did so using all factory components. Yes I did spend the time and money to do so. It took quite a while. I have done quite a bit of research on this although maybe I have missed a crucial part. As stated in my original question I am now simply wondering about exhaust manifolds. I no longer would like any sort of headers in my 68. Thank you for taking the time to follow me and I do appreciate your concern but at this point I have moved my direction and am simply moving to exhaust manifolds.

[68c20lwb]

Yes the frame has been notched to fit incorrect headers on my behalf, nevertheless not affecting mounting location, position, or fitment. If that is a concern on another level please feel free to share I am happy to listen.