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1999 0630 head/exhaust questions

sharq

NAXJA Forum User
Location
Tampa Bay
i know the 99 model year got the new style intake with equal length runners. what about the exhaust manifold? did it keep the old style manifold? the 00-01 0331 head has the smaller exhaust ports with the 2 peice manifold? they didnt put that manifold on the 99 did they? in theory the 99 should have the highest HP output of all years if it has the same exhaust port size and manifold of all other 0630 headed model years even though chryco still reported HP at 190. why would the reported HP output be at 193 for 00-01 considering the smaller exhaust ports and manifold. is my memory foggy on this or am i on the right track with my thinking here. i know we're talking about small HP fluctuations here but i love these XJs and its fun to think about.

the reason i ask is that i have a 95 and 93 so thats what i have experience with. i might buy a 99. i know all the other advantages of the 99. ie. 29 spline 8.25, HP 30, new intake. i want to know what im buying and have no surprises when i go to build this thing up.

also,i have read about the added smog equipment starting in the 99's. what the deal with this stuff? are theyre 2 cats? what other "smog" equip are we talking about here?

sorry for the winded post.
 
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No, they did not put the small exhaust manifold on the big exhaust ports. The later manifolds are cast iron, where the earlier 99 and before, had the tubular type. To use the newer manifold on the older head is a big problem. The California emissions packages, which were not limited to CA, has multiple cats, but most '00 + '01 just have the one cat.
 
No, they did not put the small exhaust manifold on the big exhaust ports. The later manifolds are cast iron, where the earlier 99 and before, had the tubular type. To use the newer manifold on the older head is a big problem. The California emissions packages, which were not limited to CA, has multiple cats, but most '00 + '01 just have the one cat.

i mostly interested in the '99. did it still only have one cat?
 
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