McJacks headers
Thread Starter
Safety Car
Joined: May 2005
Posts: 4,176
Likes: 7
From: Jennings LA
The short answer is yes. For example the Hooker 2151 super comp longtubes that everyone loves to install were designed for the L98 but can be made to fit an LT1, or in my case an LT4. Here are the changes I had to make to make them work:
-Grind a little bump off of the frame that hit one of the primaries. No biggie.
-Grind about 1 mm off the edge of the motor mounts, and reverse the motor mount bolts so the primaries do not hit.
-Stretch by hand the brake lines coming out of the master cylinder until they were out of the way of one of the primaries.
-Eliminate the AIR system and cats. (I don't have EGR, since it's an LT4)
-Pay an exhaust shop $50 to block off the O2 bung on one of the primaries, and put two more O2 bungs farther down on the collectors.
-Eliminate the stock spark plug wire holders, use wire ties and plug wire separators instead.
-Eliminate the alternator brace and instead secure the alternator to the accessory brace with a bolt and some washers.
-Re-use two of the stock exhaust manifold bolts (the ones with studs on the end) so that you can keep your A/C brace and your oil dipstick. To reuse stock bolts you must use spacers between the bolt and the header, but luckily the proper spacers were included with the headers.
-Grind a very small amount off the analog ECT sensor to allow the headers to be fed in from the bottom.
-Purchase an O2 sensor wire to extend the driver's side O2 sensor wire.
-Pay an exhaust shop another $150 to cut off the ends of your stock exhaust, and then weld flanged expanders on so that it mates with the headers.
-You no longer have bungs for the rear O2 sensors, so you must now wire up an O2 simulator to trick the computer into thinking there are still cats. If you do not, fuel trim will be adjusted slightly by the computer to try to get the cats working better, according to the FSM.
-Grind a little bump off of the frame that hit one of the primaries. No biggie.
-Grind about 1 mm off the edge of the motor mounts, and reverse the motor mount bolts so the primaries do not hit.
-Stretch by hand the brake lines coming out of the master cylinder until they were out of the way of one of the primaries.
-Eliminate the AIR system and cats. (I don't have EGR, since it's an LT4)
-Pay an exhaust shop $50 to block off the O2 bung on one of the primaries, and put two more O2 bungs farther down on the collectors.
-Eliminate the stock spark plug wire holders, use wire ties and plug wire separators instead.
-Eliminate the alternator brace and instead secure the alternator to the accessory brace with a bolt and some washers.
-Re-use two of the stock exhaust manifold bolts (the ones with studs on the end) so that you can keep your A/C brace and your oil dipstick. To reuse stock bolts you must use spacers between the bolt and the header, but luckily the proper spacers were included with the headers.
-Grind a very small amount off the analog ECT sensor to allow the headers to be fed in from the bottom.
-Purchase an O2 sensor wire to extend the driver's side O2 sensor wire.
-Pay an exhaust shop another $150 to cut off the ends of your stock exhaust, and then weld flanged expanders on so that it mates with the headers.
-You no longer have bungs for the rear O2 sensors, so you must now wire up an O2 simulator to trick the computer into thinking there are still cats. If you do not, fuel trim will be adjusted slightly by the computer to try to get the cats working better, according to the FSM.
did you get them coated after you modified thaem? are did you just leave them painted ?
Thread Starter
Safety Car
Joined: May 2005
Posts: 4,176
Likes: 7
From: Jennings LA
hooker 2149
I found a good deal on a used pair of hooker 2149 headers. they are for the L98 and have the air tubes welded to them. will they work? I can just cut the tubes off and weld up the hole. $150 used and they are ceramic coated could I make theese work?
here they are at Jegs new
http://www.jegs.com/webapp/wcs/store...1_36598?CT=999
could I make theese work?here they are at Jegs new
http://www.jegs.com/webapp/wcs/store...1_36598?CT=999
Drifting
Joined: Aug 2006
Posts: 1,326
Likes: 18
From: Los Angeles California
The cost was about $325, and I think they gave me a discount because I said I was referred by corvetteforum. They can coat both new and used headers.
Thread Starter
Safety Car
Joined: May 2005
Posts: 4,176
Likes: 7
From: Jennings LA
Sorry I missed this post. Yes, I got them coated by Jet Hot after the modifications; I wasn't going to at first, but a reason came up for me to uninstall the finished headers again so I decided to ship them off. I got their "extreme" coating for a little better insulation because the whole goal for me was lower engine bay temperatures. I have to say I can't notice the difference in engine bay temps, but I'm sure it's there and will slow down my ongoing process of plastic parts warping due to heat. The coating looked extremely high quality (and beautiful!) once I got it so I have a lot of faith in its insulating properties. I also expect my thin headers to be less prone to heat-warping.
The cost was about $325, and I think they gave me a discount because I said I was referred by corvetteforum. They can coat both new and used headers.
The cost was about $325, and I think they gave me a discount because I said I was referred by corvetteforum. They can coat both new and used headers.
Drifting
Joined: Aug 2006
Posts: 1,326
Likes: 18
From: Los Angeles California
Even though my engine bay is still boiling hot (the outside temperature probably doesn't help), I do notice that the coated headers cool down very quickly after the car is turned off, and are cool to the touch at the collectors after a short drive. Very awesome.
Le Mans Master
Joined: Oct 2007
Posts: 7,410
Likes: 949
From: Tennessee/Rhode Island
McJack Headers
I just put McJack' headers on my 78 L-82 4 Speed. These headers are a piece of art! They fit perfectly, sound great, have much more room than the stock cast iron ramhorn manifolds, are an exact copy of the stock manifolds, sound great and dramtically increased high RPM horsepower, and very importantly, hook right up to the stock 2-1-2 exhaust or OE true duals with zero modifications. Zero issues installing them or changing spark plugs. Unless you racing on a track, these headers are the only way to go on the street and cause zero road clearance problems. I waited 25 years for someone to make a duplicate of the cast iron GM ramhorn manifolds and McJack has done it!
Advanced
Joined: Dec 2004
Posts: 58
Likes: 1
I just put McJack' headers on my 78 L-82 4 Speed. These headers are a piece of art! They fit perfectly, sound great, have much more room than the stock cast iron ramhorn manifolds, are an exact copy of the stock manifolds, sound great and dramtically increased high RPM horsepower, and very importantly, hook right up to the stock 2-1-2 exhaust or OE true duals with zero modifications. Zero issues installing them or changing spark plugs. Unless you racing on a track, these headers are the only way to go on the street and cause zero road clearance problems. I waited 25 years for someone to make a duplicate of the cast iron GM ramhorn manifolds and McJack has done it!
