BBK 1-3/4 LT Fit

[misl302]

Hey All,

I'm in the process of installing some BBK 1-3/4 LT's. So far, it looks like I may have a clearance issue on the passenger side. I can't get the header bolts installed because the top of the collector interferes with the floorboard/firewall area. The exhaust ports on my Holley heads are slightly higher than stock and this causes the collector to be located a bit higher. Anybody have a similar problem? I would assume many aftermarket heads have higher exhaust ports.

 

[91RRLX]

I didn't have that problem, but they did hit the pass side of the crossmember. It required several attempts with a hammer to "persuade" it to fit.

 

[N8Miller]

yeah, mine werent the easiest to go in with the engine in either.

tip though: they will go in nicely if you take the pass. side valve cover off and go in from the top.

 

[misl302]

Thanks. I actually have the header in position, it just seems to be located too high. I'll take another look tomorrow.

 

[Grn92LX]

I have TW heads on my 347 and we just dropped the engine in yesterday. My bbk 1 3/4" longtubes have the same fu cking problem. The #4 tube is sitting on the fu cking firewall. I managed to get the header in but I think i'm gonna pull the bolts out, drop the header and bang the firewall with a hammer. I was thinking that it was because I run prothane poly motor mountsbut now that you have the same problem it must just be the design of the new bbk headers or something. My old 1 5/8" bbk LT's fit perfect.

 

[ProjectJ]

sometimes I find it easier to take the driveshaft out of the car and unbolt the trans crossmember to let it droop (with a small jack under the trans). With the engine tilted like that it's usually easier to get the headers on, then you can "adjust" the firewall as needed (not always necessary, but sometimes) for clearance as you jack it back into place.

 

[9250stang]

Did you have any issues with the steering shaft?

EDIT: Spelling

 

[misl302]

I haven't gotten around to the driver's side yet.

 

[Grn92LX]

Did you have any issues with the steering shaft?

EDIT: Spelling

The steering shaft clears fine. Its just the #4 tube on the Pass side sitting on the firewall. Im about to go outside now and unbolt that header and see if I can bash in where its hitting.

 

[9250stang]

Well, in honor of this thread, I am going to update my sig to what I used to have in there.

I installed 1 3/4 on my old '92 GT. OMG, will never do this again without a lift.

 

[TIMMY2734]

My #4 tube hits the firewall and their is a minor rubbing issue with one of the tubes and steering shaft

 

[misl302]

Ugh, the saga continues!!!

I've returned from a short vacation and resumed this project. I've "reshaped" the firewall enough for the #4 tube to clear. The headers are installed. Next problem: The header outlet flanges are 1.75" closer together than the BBK x-pipe (w/ cats) inlets. Two thoughts:

1. Were these headers designed for a 351 and is a 351 wider than a 302? If so, then the x-pipe may be designed to fit these headers on a 351.

2. Is the exhaust surface of my 17° Holley heads at a different angle than the stock heads? If so, then the headers might be pivoted such that the outlets become too close together.

Any thoughts?

 

[misl302]

I see now that there are different LT headers for a 351 and 5.0. I have the part number (15940) for the 5.0, so theory #1 below should not be an issue.

I guess I'll call Holley and see if they can tell me if the angle of their cylinder head exhaust port surface differs from the stock heads...yeah right.

Looks like I'll be modifying the x-pipe to fit.