3" downpipe/firewall clearance issues

Cat_rebel · Oct 11, 2012

Who else has em? The more I look at this thing (now that the tranny is out) the more I want to slap a set of hockey pucks under the body mounts to help it clear just a hair. I really don't see how much I can smash the firewall without having to dog house the inside & pull the up pipe off to get in there. Guess my engine & cab were set close from the factory. I fought like hell to get a 3" in there & yes, I did have to use flex pipe to help clear the cab, tranny/lines.

Can't tell in the pics but the down pipe is hitting the firewall.

Kinda makes me regret ever pulling the hoodstack off. I figured it would suck but didn't think it would be this bad since I've seen some OBS's accept a 3" DP without hardly any issue. Looking like a 1-2" body lift is about the only option I have. Other than consuming massive amounts of alcohol & going nuts with a hammer & porta power.

Stroker#66 · Oct 11, 2012

Porta power does wonders

Cat_rebel · Oct 11, 2012

Stroker#66 said:
Porta power does wonders

So what do you porta power off of to smash the firewall?

Stroker#66 · Oct 11, 2012

Cat_rebel said:
So what do you porta power off of to smash the firewall?

The cylinder head/bell housing

baderic03 · Oct 11, 2012

They are all a tight fit. And you can cave it in plenty b4 you ever notice it in the cabs

SDstroker · Oct 11, 2012

If your in the deep would it be easier to modify the dp you have? Or is it just that tight. I never worked on a OBS....

Wes Lewis · Oct 11, 2012

I got a 3in body lift on my with no dp issues, on trucks without a lift I thought it was just bend the pinch weld and slightly bend in the firewall. Hardly any on the truck I did.

Just a thought, with out your trans in did your motor rock back any?

Bugman · Oct 12, 2012

You can also loosen the motor and transmission mounts and see if you can slide the engine forward a little. I have seen a couple of trucks that the down pipe slid right in just because of the position of the motor and transmission.

SDS97_7.3 · Oct 12, 2012

Cat mine looks almost the exact same way as yours does fit wise.

PSDEng · Oct 12, 2012

They suck to do, but with all that carnage in there I can't tell at all in the cab.

bluedge8 · Oct 12, 2012

I used a scissors jack against the bell housing, wrecked the jack and was worried about putting a hole in the bell housing but it turned out well. And you probably wouldn't need flex pipe if you bought a aftermarket down pipe- or did you?

Cat_rebel · Oct 12, 2012

Wes Lewis said:
I got a 3in body lift on my with no dp issues, on trucks without a lift I thought it was just bend the pinch weld and slightly bend in the firewall. Hardly any on the truck I did.

Just a thought, with out your trans in did your motor rock back any?

Pinch weld was bent over, it's hitting on the fire wall. Even with the tranny in there it rattles in the cab.

bluedge8 said:
I used a scissors jack against the bell housing, wrecked the jack and was worried about putting a hole in the bell housing but it turned out well. And you probably wouldn't need flex pipe if you bought a aftermarket down pipe- or did you?

Could be me but I still am not keen on the idea of pressing against a cast aluminum bell housing with a jack. I am using an aftermarket down pipe.

Wes Lewis · Oct 13, 2012

Cat_rebel said:
Pinch weld was bent over, it's hitting on the fire wall. Even with the tranny in there it rattles in the cab.

Now that I think about it, I used a bottle jack on the ground and a piece of pipe to get a little extra clearance, and a big pry bar off of the back of the head

strokinfarmtruck · Oct 14, 2012

3lb sledge hammer did the trick for me

Nodge · Oct 14, 2012

Baseball bat, multiple pry bars and hammers, whatever you can fit in there. (that's what she said!)

Tom S · Oct 14, 2012

That down pipe looks like it crosses the firewall area too low to me from the pics. There is a also a quite a a bit of play in how the cab can be positioned that will effect the clearance.

bluedge8 · Oct 14, 2012

has anybody tried sliding the motor forward and or the cab back? when they have these issues? I also noticed when I did mine that where it fit the best was not where it looked like it would fit the best