`73-87 Hooker LS headers in a 67-72 C10???

[Street Smart]

Great pics @OKGMC4 thank you !

[OKGMC4]

Sorry it took so long. Got a broken rib and it hasn't shut me down but I'm moving a lot slower than normal.

[Street Smart]

Wow sorry to hear that, thanks for keeping us updated.

[OKGMC4]

Update to the update...Don't know if it was changing the motor mounts or moving the engine back but the angle of the engine changed. Used to be 3 degrees negative at the output shaft. Now is 5 degrees negative. Tried to jack up the transmission to shim it and it hit the floor. SOOO...I ended up cutting the floor and buying a high hump from a 4 speed truck. It gave me the space I needed for the trans but I had to jack the trans nose an inch to get the angle I wanted. Good news is that by lifting an inch the headers are now flush with the frame rails. Bad news is that I get to build a new cross member because it's in the way of the exhaust.

[Daryl87]

Thanks for the info from everyone who has posted.

I finally got my 6.0 and 6-speed trans sitting in my frame so that prompted me to come looking for headers.

Next step is figuring out the trans mount (truck was originally 4-speed manual, but converted to TH400 years ago). I have the tailshaft sitting on wood blocks right now so the angle is wonky. Had to move the crossmember back to the second set of holes but that makes it line up.

But the conversations on here have me wondering about engine placement. I switched to '83 motor mounts with the clamshell using the TransDapt adapters (Part #4572). Everything is just in for a trial fit right now but I noticed that my engine is sitting back quite far compared to the engine in the pictures posted above. My cab is at the bodyshop so I can't place it on to check on placement with it yet.

I came looking for exhaust ideas and I leave with many questions about fitment issues with motor mounts, linkage, crossmembers and frame rails! You gotta love hotrodding!

I think I might have to play around before tightening everything up. I might bite the bullet and order some headers so I can trial-fit them too.

There is so much great information on this site, it's just finding the time to sit at the computer to look it up!

[OKGMC4]

I believe that since you have the 73-87 mounts you'll want to look for 73-87 headers. Those mounts do move the engine back, and I know the Doug Thorley 324y headers so many people use don't fit the 73-87 trucks because of firewall / booster clearance. Good news, since you have a 4 speed truck you probably already have a high hump floor. I had to cut the floor and install a high hump after the engine moved.

[OKGMC4]

Look at the placement of the motor mount bolts in relation to the K member. I think your engine is sitting exactly where mine is. Just farther back than stock.

[OKGMC4]

And the trans cross member I ended up building.

[Steve Cole]

Originally Posted by OKGMC4

Lovin these. I am convinced that the original mounts would have fit if I'd had slider plates instead of the solid ones. With the engine back there's lots of room.

I'm a little confused, which headers are these? Do they hang down below the frame rails? Thanks

[OKGMC4]

Originally Posted by Steve Cole

I'm a little confused, which headers are these? Do they hang down below the frame rails? Thanks

The headers in the post above are Dougs headers part # D314 for 73-87 C10. 1 7/8" primary, 3" collector. They do not hang below the frame rail (once I got the trans angle correct). For them to fit you have to use the motor mounts (clamshell style) from a 73-87 pickup. This will move your engine back a bit compared to the 67-72 style mounts.

[Daryl87]

First of all: Really dig those covers on the engine! Might seem stupid but the look of the LS vs the 'old school' engines held me up for a while. They just don't look as cool.

Thanks for the feedback on the engine placement. I also tracked a guy down that put an LS in a '69 Chev and it's sitting in the same spot as mine (and apparently as yours) and has lots of firewall clearance. He is using the BRP Hot Rods kit (engine mounts, headers and trans crossmember).