I have a good but kinda secretive former Oldsmobile Engineer friend. I preface this with the fact that he was an OLDSMOBILE Engineer.. I will say in a few why THAT is Important.
CK has built now two Northstar Powered 89 Pontiac Fiero GT's. The 1st with the stock power train from a 2003 Seville STS rated at 325bhp, the last with a moded power train from a Cadillac XLR-V, which is the HP version of Cadillac's XLR Roadster built at the Bowling Green KY Corvette facility, reason being it is built on the 1st C5 and Now C6 Corvette platform. Other than tires and wheels, the STS powered car looks and sounds pure stock tho not like the V6 the cars came with; However, at the track it runs smoky 60 ft mid to low 12's at from 111-114mph w/ 2.+ 60 fts on a set of BFG 275 60r 15 TA Radials.
The XLR-V car has yet to b seen track clocked, It has a G-Tech on board clocking computer atop the dash. As far as i know he has NO plans to EVER track clock the car at a track, says this is his " Street Race" car so it really doesn't matter what it runs at a track, the car also has a FIXED lap Top computer interface with which he tunes and tweeks the car.
The car uses Weld Drag Lite classic wheels 3.5 x 15 Frt Runners and 10 x 15 rear with 28 x 11.5 x 15 MT ET STREETS. The car has a knarley raspy exhaust note much like a DOHC hgh end V8 import and from eyeballing treeet test passes i guess the car to b SOLIDLY in the low 10's since i have seen him BEAT mid to low 10 sec track clocked street rods like a drum. That will give you an IDEA of how far u can go with the Northstar Engine ur using tho it will b somewhat expensive. Thus far there is little or NO after market support for the Northstar engines, such that anything u get for one in the way of HGH PERF must come from OLDSMOBILE, which is the GM Division thet you now know as Saturn. Contrary to popular belief OLDSMOBILE was NOT deleted from the GM Family, Oldsmobile division was morphed intop a division who's mantra is to compete with the imports on an EVEN footing and on THEIR terms, a task it has proven quite adept at.
Oldsmobile has always been GM's Skunk Works Research and developement Division, 1st crse control, electric windows, auto trans, AC, OHV, all aluminum Engines, Pwr steering, pwr brakes, and many many more were researched, developed and 1st appeared on OLDSMOBILES.
As for Cadillac, as long as its been a GM name plate THAT IS ALL it has been. Cadillac, along with its sister company, Lasalle was aquired by Buick, which is the parent, founding and incorporateing Division of GM to be an UPSCALE super Powered Super Luxo Buick w/o the Buick Name. in fact the sister company Lasalle was absorbed directly into Buick become a Buick MODEL, the Buick Lasalle. Effectively, Cadillac is yet a Luxo Buick with an Oldsmobile/Saturn engine, indeed a comnplte Oldsmobile power train until Hydramatic became a seperate division from its parent division OLDSMOBILE at GM. Olds/ Saturn is the engine developer and producer, while Buick is all the other production and final assembly Division, including the body AND Painting. BUT for the XLR-V, ALL Cadillacs are built in BUICK facilities and accounts for why GM's BOC(Formerly BOPC) division is and always has been GM's largest Production Group, in fact, in GM Hierarchy The CEO of BUICK is second in command only to the CEO of GM itself and ALL GM aquisitions, which includes BUICK itself, were AQUIRED by BUICK. effectively, but for GMAC, which is the only division of GM that GM actually created, is a great big company comprised of Buick Aquisitions, in fact the Chevrolet and GMC divisions werte created HERE in Flint in already existing Buick Facilities, with predominantly existing Buick employees, BY BUICK; Chevrolet to prode an entry level vehichle to compete with the model T and Model A Fords, while GMC's mantra is and always been the production of truck/bus/van chasis Vehicles, no matter what brand name may appear on one of these, its BUILT in its entirety by GMC, even the famed Chevrolet does NOT produce a van or truck chasis vehicle or SUV platform in spite of being the most prolific name plate to appear on such rides from GM.
Until the advent and release of the Old Cadillac all aluminum 4100 V8's there has NEVER even been an engine SPECIFIC to Cadillac alone, even the NorthStar is based on the Olds Aurora V8 who's heads are based on the Olds Quad 4 4 cyl. in the days of the monster sized Cadillac V8's, these were simply OLDSMOBILE blocks with reversed oiling systems and the distributor flange moved to the front of the engine, the latter because Buick is final assembly and they wanted the Cad dist in the same place as is the V Buick dist for ease of assembly. next time get a chance, look at the Older cad 425/472/500 V8's and it readily apparent that this is actually a modified Olds engine, compare a Northstar to an Olds Aurora V8 and u will see this too is an even LESS modified Olds Engine, the diffs are internal, the Aurora V8 is but 4.1 litres while the Northstar is 4.6 and a slightly Physically larger casting, the same as the Olds 260-403 SB castings are slightly physically smaller than are their 400/425/455 castings.
If u access the GM power train division u can find a wealth of tech info on modifications and improvement for Cadillac's Northstar V8. with ur modifications, keep in mind ur actually working with an OLDS engine, thus the most effective upgrades and hop ups for performance are the same as they would b with an Olds V8. Therefore, Olds After market suppliers such as Holman Moody and others can give u tips on cam profiles and such to hop up cad engines by perusin those profiles designed for the small block Olds 260-403 V8 and pattern ur profiles accordingly.
I would LOVE to see you take the Northstar to a safe limit with that stick shift trans behind it, i think not only YOU but everyone else would b QUITE surprised.
I'm a GM BOPC fanatic from the word go, in fact my 1st ride, which i bought in 1963 was an Olds, a 59 98 Convert. Tho my predominant BOPC ownership has always been Pontiac, my fav is actually Buick, however, i have bought, built and raced a number of Olds combo's as well, which as i say, is what ANY Cad engine is, Good luck, and way to go. that has got to b destined to b an even more unique build than is my Stage 2 455 Buick Powered BMW!!!!!