Guru_4_hire

How much does one have to mod their tranny cross member for a 3" exhaust?

I have "heard" that people managed to get a 3" exhaust through the stock crossmember.

norvalwilhelm

I cut the bottom out of my holes and reinforced the sides. My 3 inch passes partly through and partly under

Guru_4_hire

how did you reinforce the sides

72 RAY

I did the same thing as Norval. Only mine is not removable!
I just cut out a chunk and welded in a piece of C-Channel to box it. I did this with the body on. Not to bad as far as projects go. Just have to make a good straight cut so you don't have fill with the welding.

rihwoods

Think I read here some squeezed 3" thru..just barely...???

Twin_Turbo

3"fits through without mods, it's the tranny that's close when running 3" because the holes in the crossmember are so far inboard

Aflac

how much horsepower are you looking to have?

Jason Staley

It's a close fit, but can be done. I've had my exhaust on for a year now with no rattles. Used wood shims when welding up bracket on x-member to center tubes. Clearance to trans was about 1/2", but since motor is mounted in polyurethane, that's enough room my setup.

norvalwilhelm

I actually filled in the original holes and cut half moons further outboard. I wanted to keep the heat away from the transmission and also run staright back from the headers.
I cut out 1/2 moon and then used 1/4 inch plate front and back and welded it to the crossmember leaving the 1/2 circle out for the exhaust.

Twin_Turbo

I'm building a new one from scratch but don't have the exhaust holes in it yet...and the pic quality sucks. I'm going to cut some large notches in it to clear a set of 3" equiv. oval pipes.

norvalwilhelm

marck where are the holes?? No way I would leave anything solid like that. Holes way nothing.

GrandSportC3

Just go with 4 inch sidepipes.. No clearance problems

norvalwilhelm

Open side pipes on the street are not a option. It is totally irresponsible. Just because you like the sound of your car doesn't mean that everyone else does. Here it is totally against the law and asking to be hasseled. Corked up side pipes are not as good as a 3 inch full exhaust anyway.
I also value my hearing and you will suffer hearing loss dumping a loud exhuast directly by your ear.

GrandSportC3

You can always put STS baffles into the side-exhaust and still have good performance... I drove over 40k miles in 2 different Vettes without any mufflers and my hearing is just fine... Especially with overdrive in my '68, the noise ain't too bad..

Twin_Turbo

Don't worry..there will be holes in it for sure. I'll do that after I determine the final position of the notches for the exhaust piping, no sue in drilling holes to find out they intersect with a notch...that would look ugly.

Guru_4_hire

Well the fun and joy of the hooker headers is all well and good but

1.) I cant hook them up too turbochargers
2.) the primaries are too long for a low RPM range
3.) My calves already have enough scars on them
4.) they look weird on non-chrome bumper cars

But seriously, I seriously thought about them. On a BB 427 with a L88 cam or equivilant solid roller, I would be all about them.

Techno

What?