Headers on a 454

[ghostflyer]

I'm in the process of putting a set of headers on my 86 1-ton. I removed the factory SS headers with great difficulty. (every bolt was seized). I'm wondering about the torque for the header bolts. The manual says to torque cast iron manifold to 18 lb-ft and the SS ones to 40 lb-ft. Quite a difference!

Since the headers are built with a plate like the factory SS manifolds, should I use the 40 lb-ft for the headers also. Seems like a lot for those small bolt heads (3/8").

Thanks,
Les

[donut]

When I did mine, I didn't use a lot of torque. (IIRC I used a 1/4" drive socket set and/or a wrench.) IMO, the key is to run them a bit, then re-torque.

Maybe someone else has the actual torque spec.

[ghostflyer]

Since I had such a hard time getting the original bolts out, I oiled the holes and ran a bottom tap into each hole. I have them torqued to about 25 lb-ft. All the bolt torque tables that I have checked show about 30-35 lb-ft for a 3/8"-16, grade 5 bolt dry and 23-25 oiled.
I will retorque them after they have been warmed up a few times.

[ghostflyer]

Finally had day with decent weather to finish the header job. I put the original spark plug wires back on, complete with long rubber boots and metal shields. They fit OK, but are very close to the header tubes. It looks like a shorter boot that angles up would get the wires into a better position.
Does anyone have a suggestion of a better way?
Thanks, Les

[donut]

Many different setups will work, depends on what your looking for, (I'm sure longtime big block owners will chime in, I'll be watching also)

Personally I went underneath. Found a set of Moroso under the header wires, so they're pretty much hidden. 90 deg. boots with enough length to run underneath. I needed new wires anyway. I think someone used smallblock wires on it before, they were pulled guitar string tight.

[bilfman]

I have had headers on a multitude of chevys for over 30 years, the key is several retorques for the first several drives. I just installed a new set on my 454 and it took 5 drives and torques to get them settled. I have not had any trouble with header bolts not coming out. I always torque them by 'feel' after wrenching for so many years you get the feel for what the bolt will handle, I use this method for headers. Basically a max torque situation. If you like opening the hood like I do, a quick retorque every few months doesn't hurt. It is quick. That said I have always been happy and satisfied with headers using this method.

[bilfman]

I just read your post closer and saw your plug wire issue, big blocks with headers like to touch plug wires. A fix for this is Accell make a premade wire set, they are a streetfire 8mm if I remember correctly. They are a long straight boot design. The deal on these is that the long boot is bendable, put in a phillips screwdriver or if you are tough use your hands and you can bend the boot so the wire does not hit the header.

[shipma2]

the previous owner put headers on my 454 in my truck