NHRA Line-Loc requirements
 

I am planning on installing a line-loc on the front brakes of my 87 IROC. According to my understanding of the NHRA rulebook, a line-loc device must be installed downstream of the differential pressure switch located in the combination valve on these cars. The problem is that each front brake has a separate line comming out of this factory valve. Does anyone have any advice on how to route the two separate circuits through a single line-loc solinoid ?? I really don't want to install two line-loc solenoids.

There are 2 ports coming out of the switch for the front brakes. You plug one of them. The other goes to the inlet port of the line lock. A tee fitting is used on the outlet port of the line lock and both front brake lines are connected to the tee fitting.

I haven't installed one on my car yet. Mainly because my car uses metric brake lines and fittings. All line locks use standard fittings. You can either replace all the lines including the pressure switch to standard or by using adaptor fittings which might be a better option.

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and check out the race car

87 IROC-Z Pro ET Bracket Race Car
383 stroker (carbed) with double hump cast iron heads and pump gas
461 Big Block installed and ready for the 2001 racing season

Best results before the 383 blew up
Best ET on a time slip: 11.857 altitude corrected to 11.163
Best MPH on a time slip: 117.87 altitude corrected to 126.10
Altitude corrected rear wheel HP based on power to weight ratio: 476.5
Best 60 foot: 1.662

Racing at 3500 feet elevation but most race days it's over 5000 feet density altitude!
Member of the Calgary Drag Racing Association

87 IROC bracket car, 91 454SS daily driver, 95 Homebuilt Harley

Thanks for the info. I wasn't sure if it would be ok to run both front brakes off of only one port on the factory combination valve. Does anyone know where to find the adapter fittings ?? I haven't checked, but my lines are probably metric as well (they are the factory brake lines).

I "think" Moroso sells the adaptor fittings. They aren't cheap. You might also want to check import shops since they want to use line locks also and have metric lines.

You can do the install with the $50 line lock solenoid from Jegs if you buy some lengths of standard brake line with standard fittings on each end, a mating flare tee fitting, a mating female - female flare coupler fitting, a tubing bender, and a dual flare tool from NAPA, or any auto parts store. Cut the front brake line that points down from the proportioning valve near the prop. valve & pinch the end of the line off that has the fitting on it - have the line welded closed - this will plug the lower outlet from the prop. valve. Cut the other front brake line & leave about 4" of line on the end that has the fitting installed on it. Install a standard flare fitting (from one of the the new standard fitting lines) on each of the two brake lines going to the front slave cylinders and also on the cut line coming from the prop valve. Use the coulper and a standard fitting line to connect the line coming from the prop. valve to the line lock solenoid inlet. Use another standard fitting line to connect the line lock solenoid outlet to the tee. Connect the lines going to the two front slave cylinders, which now have standard fittings on them, to the tee, as well. I did this on my '92 Z & it works great.

Tim