zblee

Edit: header fitment may be caused by sagging (not broken) motor mounts. If I end up getting new motor mounts at some point and find that it was the cause - I will update this thread

I just installed my headers this weekend on my 2003 silverado RCSB 5.3l 4l60e 2wd. I had fitment issues on my passenger side headers. The headers would not mount up flush without modification to the tubing. The frame is not bent and the motor mounts are not broken. Initially the fitment issues were really bad, but this was due to the transmission resting down further than normal. To get the original y pipe out ( and install new y pipe) the transmission cross member needs to be removed and the transmission held up . We held the transmission up with a floor jack and overnight it must have dropped an inch or two. This made the header fitment really bad, after noticing the transmission was low, we jacked it up (actually higher than if it where sitting on the cross member) and we still had header fitment issues. Ended up flattening out , unfortunately , one of the pipes that was hitting the frame. I originally posted this in their sales thread but I was asked to remove the post , so I removed it and posted this here.

This picture was before jacking the transmission up where it should have been, so this is exaggerating the issue a bit, but like I said, even after lifting the transmission up , the header still contacted the frame enough to not allow flush mount of the header flange to heads. I will try and post pictures of the headers installed.



If you are using the supplied bolts that come with these headers - please use a washer. The holes ( at least in the center of the header flange) are too big for the supplied bolts. I was torquing the center bolt and it started to cut into the flange , luckily i was able to back it out and bought some grade 8 washers (along with new header bolts) and used these on each of the 12 header bolts (the new ones i just purchased) just to make sure that did not happen again..



New passenger 02 sensor location works and no clearance issues , I am hoping the angle is enough to not cause condensation issues with the sensor...



Y pipe runs right along the front of the transmission cross member running right underneath the back end of the transmission pan. It does not touch but it is very very close



_Zblee

ezdaar

iTrader: (1)

Your mounts are sagging bud.
And should have know not to use those bolts. You knew to get better clamps..
Loosen your trans crossmember. Use a jack to lift it as high as it will go then torque the cross member bolts back down.
You will gain cross over pip to pan clearance.

zblee

I think you are right on the sagging part, I thought that either the motor mounts are broken or they are not. I would not have ever guess that they would sag almost an entire inch?

I did not know to not use those bolts, I never saw anything online telling me otherwise . I did however see some information on how the supplied clamps are not the best , so I got band clamps instead.

That is a good idea with the cross memeber, I will have to try that and maybe gain another 1/8" or so.

ezdaar

iTrader: (1)

Look closely at your mounts, and you might see the inner and outer shells touching..

Will be very easy to determine by eyeballing, then jacking up the engine and eyeballing again.

I've only ever had "good header" frame clearance issues when I had sagging mounts.

Can't say 100% that's your prob, but, just a long term observation.

JohnDaMan

iTrader: (7)

The speed engineering headers rubbed with old mounts and new mounts on my buddy's VMax truck. Take it for what it's worth. Get the torch out, heat them up and bend them a little.

The Fitment of the Cal-Speed headers on my truck seemed better honestly.

chadjcompton

I installed Speed Engineering long tubes on my 2007 silverado classic VMax about a month ago, they were the 1 7/8" headers. I had no fitment issues. Granted i had custom exhaust ran from the headers all the way out, I didn't get the Y pipe. But my exhaust shop said they headers were the best fitting $300 longtubes he'd ever seen.. hope it works out

Speed Engineering

iTrader: (35)

No heating or modification should be needed with our headers. I was emailing zblee over the weekend about the motor mount issue, but I guess didn't believe me lol. We have seen one other case that I am aware of where the header hit the passenger side frame rail, and it was fixed with a motor mount swap.

JohnDaMan: Were the headers you installed our 1 7/8" 99-06? If so our first batch of those were closer than usual to the passenger side frame rail. They have since been pushed in approx 3/8" of an inch to help with clearance. Our 1 3/4" shouldn't have any clearance issues however. We have sold a bunch of those without any complaints, and no modifications have been needed besides the O2 Bung location. Which, has also been fixed in this current batch.

Thanks
Sean

JohnDaMan

iTrader: (7)

1 3/4" on an 06 VMax. Both sides were actually rubbing. The only difference other than stock is the heads were milled .020, but I don't think that was the culprit.

Speed Engineering

iTrader: (35)

Both sides? Our headers are not even close to anything on the drivers side to rub. Can you please send us pictures so we can figure out what might be going on in your situation.

Thanks
Sean

X_Racing1

Hey speed are these a direct bolt in replacement for the manifolds?
Speed Engineering Shorty Headers Truck & SUV (1999-2013)