Thread: 98 Riviera 3.5 pulley swap

Hi guys.
So after selling my gt i picked up a 130k rust free 98 rivi, i was given all maintenance records that indicate intake gaskets, valve cover gaskets, and super charger couple have all been replaced recently. So i feel safe to start modding. A couple things i will order with mods are colder plugs and a tune. I will also be buying a scan gauge. Now i cant seem to find anything set in stone on whats safe to drop to without major mods like headers. With a intake, tune, colder plugs, 180 t stat and being as the rivi has no u bend would it be ok to go straight to 3.5? I was thinking of doing a dp but i eventually want to go headers and drop to a 3.4. Zzp says without headers a 3.6 is it, but why would it be ok to get rid of a u bend, toss in a t stat and tune in a gp and drop to a 3.5 yet not in a rivi or bonneville? Thanks guys. Im excited to pull the trigger on my shopping cart, this build will be a step by step process just like my gt but id like to be in the 275whp range by next spring. This is a crap hole picture of the car but i wanted to give ya something

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There is literally a guide on this very forum that discusses modding the 3800 safely. Have you read that post? Your primary goal should not be immediately dropping to the smallest possible pulley you can run.

We can't tell you if it's "safe" or not. You need to be scanning the car and seeing what it's doing. Once you have your intake and tune and whatever else you want, scan the car and see what your KR is looking like. Still have KR? Don't drop the pulley. Personally, I wouldn't drop to a 3.5" on a G/H-body without at least a front Plog. At least the rear manifold situation is better on those cars than the W-bodies.

All i wanted was a personal oppinion on it, thank you i wont drop any lower than a 3.6 untill i get headers. I have read and read the safley modding you 3800 thread not only here but on the riv performance forums and i know whats required and that maintenance first is key. Its just most threads/posts and write ups i can find are back and forth about what size is ok on minimal supporting mods. Zzp says nothing lower than a 3.6 before headers, you recommend nothing lower than a 3.6 before atleast a plog so i think i will play it safe and go 3.6, fwi, tune, al104's and 180 tstat. Im sure its an exaggeration but turbo tim from zzp says that combo in a g/h body is good for 220+whp

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