Hey guys, I'm baaaaaaack. Hell, none of you probably remember me over here! LOL

I have a question for LT1 swappers who have headers. On my RS I have the SLP 1 3/4" shorty design. Since DAY ONE I have had an exhaust leak. Including engine rebuilds, I have pulled the headers and tried to eliminate the leak 5 or 6 times now. Its funny how every time I do that the leak seems to change sides of the engine. But it is almost ALWAYS with the 3,5 and 4,6 center exhaust flanges.

I have GTP stage 2 heads on the car and the exhaust ports have been cleaned up a bit. Right off the bat I recognize that the area available for a positive seal at the bottom of each exhaust port is fairly slim w/ the SLPs I have. Another problem w/ the SLPs has been that they are a BITCH to get the bolts socked down.

So I'm wondering..... what brands have people used that have presented no problems? Also, who else has run these SLPs and have you managed to be leak-free?

Lastly - does anyone have some tips for getting rid of the leak? I've already tried the thicker Fel-Pros and they have done better than most.

Right now I am thinking that some ARP exhaust studs would help. And if I can, I'll try to cut the silly bolt tubes off.

 

can't help you. mine leaks like a mother... I've tried just about everything, but for some reason the rear bolt on the passenger side continually backs out no matter how tight I get it. 2 weeks later, its leaking again. I'm replacing the gasket this weekend and putting lock washers on all of the bolts to try and get it to seal, hopefully it will work.

I've learned to live with the collector gasket leaks. Its a lost cause trying to seal those short of welding them up.

Oh yeah, I'm running Hedmans.

 

You're running pretty well there. Definitel C5 competition! When it was bone stock, my '00 6-speed pulled a 13.0 @ 109.52 Talk about FRUSTRATING!!! So close to 12s. That was my last run for the night before they started the event for that afternoon. If they had let us stick around and take advantage of the night air I'm sure I would have snuck into the 12s.

Welding........ hmmmmm... tempting........ LOL It's true, I've had it with the leaks. It is just so audible in my case that it is driving me nuts. I have bought two SLP products in my life, and in both cases they have turned out to be heavily overpriced pieces of crap. The SLP loudmouth does SOUND great on the C5, but its quality is for crap. The pipes don't sit even and are even a bit crooked despite hours of manipulation.

I don't know about your Hedmans, but with the SLPs we don't have one solid flange across the exhaust ports, so its tough to sock it down correctly. On top of that, our bolts don't sock down right to the flange but to the ends of these extended bolt "guides" or tubes. That just can't equal the same type of seal pressure. And all of this is being pressed down on a gasket and flange which forms a seal maybe..... 1/16 or 1/32 of an inch wide on the bottom end of the exhaust ports. Pain in the ***.

My buddy Mark (markolc) has longtubes on his and they are perfectly sealed. The catch with his are that they bang all around his frame and suspension pieces. So which is better...

 

I have Stage 8 locking header bolts on mine and they worked like a charm on the drivers side. That was the header I put on with the motor out. The passenger side on the other hand I can't seem to get tight enough and have a leak at the middle two cylinders. It's driving me crazy but one of these days, I'll try and get in there and see if I can get another turn or two out of them....maybe that'll help.

 

Try some of the soft copper gaskets on both the head and collector, maybe two per side on the collector as they are really a poor seal. They last longer and help the bolts stay tight. Les

 

Guys, I don't know if this will help but I will give my view.

I'm building a 400 (.040 over) with GM FastBurn heads. These heads use exhaust ports similar to the LT1s (D-ports).

I also have a set of SLP 1-3/4" headers (no smog tubes).

Guess what? The SLPs are not truly 1-3/4" at the flange where the tubes are welded. More like 1-3/8". Yes, the tubes are 1-3/4" but the flange opening is not!!!

I had decided to go ahead and "port" my header flanges to match the exhaust ports---which are about 1-1/2"wide across the opening (at the bottom of the D). But after looking at them a couple of weeks ago, I decided there would not be enough material left to seal the gaskets properly.

What may be happening in y'alls cases may be the 'stock' opening header gasket is overhanging into the "D" port and getting burned between the two-center exhaust ports and eventually burning out far enough until it gets to "fresh air". Could be. Maybe not.

By the way, anyone know the Hooker measurement at the flange-to-port opening? Not a guess but a true measurement.

Thanks,
jms

 

I have earls header gaskets on my car. They have a metal gasket type thing with replacable inserts. I have had them on for 3000 miles so far without any problems.
Kory