Currently i'm shopping for a car, and the 98+ trans am is looking to be high on my list. Before buying, i like to look at aftermarket parts, seeing how much they are and so forth. I'm used to mustangs, so seeing these high ls1 prices is kind of scary. One thing did strike my curiosity though. . .. . between 98, 99, and 2000, what differences were made to the motors? I was looking at slponline.com at the power packages, and they have kits being advertised for 2000 or 99's, but not for 98's. Why wouldn't a 2000 kit work with a 98??? or vice versa, why wouldn't the 98 kits they sell work with 2000s?

here are twi kits that i'm talking about:
98-99 350hp kit:
http://www.slponline.com/view_product.asp?P=28021

99 375 hp kit
http://www.slponline.com/view_product.asp?P=28026

2000 400hp kit
http://www.slponline.com/view_product.asp?P=28035

i'm just curious as to why, for example, the 2000 kit wouldn't work for the 98?? Any info would be appreciated, thanks.

 

https://ls1tech.com/forums/new-ls1-owners-newbie-tech/213148-jrp-s-faq-commonly-asked-questions.html
Check out the link to differances between years. Also DON'T waste your money on those slp packages. Those power #'s there giving you are not rwhp.

 

https://ls1tech.com/forums/showpost....0&postcount=39
lol yeah there over powred! lol read that thread to let you understand whats whats and you should be set! oh and the prices on these parts are normal, just think of it this way, you only have to buy 1 or 2 parts to equal out what alot of other parts for the stanger to make the same power

 

https://ls1tech.com/forums/showpost....80&postcount=2
That'll give you the year by year differences
Before you do any mods, read the forums,(use the search button) they'll save you some time and $$$ by giving good advice on what works and what doesn't
Good luck with your search

 

The only thing i can see thats not directly interchangable in those kits is the lid for the 2000 since it had the line for the breather filter in it there is a hole in the lid for the hose, i know for sure the 98's dont have that extra hose so you'd have to cap the hole to make the lid work for that car, and cut a hole in it to make a lid designed w/out the hose to make it work for the 2000, but that stuff is a waste of money essentiall, and 1.8 rockers really arent worth it if your gonna cam it, most companies suggest against them, i'd say get your year or choice, tranny of choice and cam/headers/clutch (or converter/shiftkit/cooler) and see where your at then.

 

I would say try to go for a 2000, or even a 01 if you can afford it because 01's and 02's have the best flowing heads and have an LS6 intake......

 

Thats some misinformation. '01-02 heads are the same as 99-00 heads, and do not flow any better. Its the LS6 intake on the '01-02 that add about 10 hp, not the heads.

 

241 cast heads were Die Cast which is a process that smooths up the ports a bit compared to the Sand Cast procedure that was done on the 806 and 853 heads. Once ported any "advantage" the 241 cast had is moot.