i was wondering what size pulley would be safe for a l67 with a polished and slightly ported supercharger, foy racing headers and exhaust and autolight 606 copper sparkplugs? or should i just keep the stock 3.8" pulley?

Can't say for sure but a 3.4 is alright for a relitively stock l67, so you should be good with that and lower, get a colder thermostat. Cheers

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86 Fiero GTX project soon to tear up the street, My build thread! 3800sc, interior, wheels and more! https://www.fiero.nl/forum/Forum1/HTML/089483.html

I'd go with 104 copper plugs. A 3.4 should be safe with headers. Just make sure you scan for KR.

what would you say for a tstat? 180? also whats the best way to monitor kn? i read some thread about gtp guys using a 1v led tied into the obd-2 i believe so it blinks everytime it senses kn

quote Originally posted by jake88gt: what would you say for a tstat? 180? also whats the best way to monitor kn? i read some thread about gtp guys using a 1v led tied into the obd-2 i believe so it blinks everytime it senses kn

Yes 180 should do it, well if you do a scan with a hand held tuner and you have no knock retard then you should be golden unless something happens and your KR's magically shoot up?

thanks for the info! sorry for all the question haha

We are running a 3.2" with our headers, ported sc, tb and exhaust ports, 104 plugs and 180 tstat

This is with 2004 GTP spark tables on a 98 PCM with no knock. But, we can't guarantee you will be able to do the same. Get yourself a tuner

Nearly every 3800SC SII should be able to run a 3.4 with just plugs tstat and a good exhaust

[This message has been edited by FriendOfYours (edited 10-15-2012).]

All motors are different so there is no certain answer so buy a scanner a scan. Most common though on a 3800 Fiero swap a 3.4 is considered stock on the Gen 3 if you have a open exhaust and 3.5-4 inch intake. With headers, 4 inch intake, 3 inch exhaust and some AL 104s a 3.4 will be good but scan to insure. A good tune gets u the most....