What emissions can i remove for more HP

[littlesdrag]

Have a 79' cj5 and I've seen from 1975-1979 jeep the 304cu lost nearly 60 hp. Y'all have any ideas of what I can do to create more HP? Think I'm gonna put on a set of headers. If I come across a set of heads, can you put 360amc heads
On a 304(and is it worth it)? Thanks for the help......

 

[69jeepcj]

It would be my guess that the Hp diferances were in the cam, heads and mybe the carb they used on the engine. Headers will give a gain, around 15hp. I would look into a cam. Its easy to do and can increase hp a lot.. Comp cams website has a page you can plug in all you info and it will recomend dif cams and give the hp rating of that cam for your set up. You can get a cam and lifters for about 100 buck. If you put a cam in it and headers, I think you will be happy with the hp.
I dont know about the 360 head swap, seems Ive heard that they will not fit though.

 

[superj]

I have no idea but will be reading along for future info

 

[carnuck]

Catalytic converter is one big cork in the exhaust system. A higher flowing cat helps (the internals of mine ended up in my muffler)

 

[JohnnyO]

The cat and the air pump if it has one. Then get it dyno tuned if possible to get the carb and ignition adjusted and recurve the distributor. Headers are good. With all that, a '79 may still pass emissions. Vehicles from about '82 and newer will run better with smog equipment intact and mods designed to work with it.

 

[gearheadmb]

Emissions may be a part of the hp loss but there also was a point in the 70s when the manufacturers changed the way hp was rated. Previously they dyno pulled them bare, no emissions, no fan, no alternator, etc. Then they changed that to dyno testing an engine the way it actually is in the vehicle and then everybody lost quite a bit of power. That may be why youre seeing such a difference in hp ratings.

 

[carnuck]

The change from Bulk HP (motor alone) and Net HP (with all accessories attached) was '72. The addition of AC, higher output alt, PS took away some power. Cats were required by '78 and early ones are a clog. Replaced mine with an anerobic high flow one and the emission numbers dropped and fuel economy went up. Got $40 for scrap for the old one (due to platinum in them. Modern ones don't have it)