(long post)
Yeah, $3000 sounds about right for a minimum stock V-8 swap. But stocker V-8 didn't cut it for me, no matter how good they make it look at JTR.
I spent about $2,000 for the motor alone that had a Competition cam, and some decent iron heads. After burning it up, my friend mas28O hooked me up with City Motor Supply in Dallas to get some sturdy 4-bolt blocks for about $250 w/ core. Went through about 3 motors for various reasons, and I needed that connection.
BEFORE I did the swap, I had already spent $1700 for body work and paint, about $1,000 for wheels and tires, and countless mega-bucks trying to get the inline-six to go fast which was mostly a waste. The best I ever got the six to go was probably low-15's, right about even with some stock 5.0's on the road at the time.
Now having a mid to high 13-second Z wasn't enough for me. I wound up spending a lot more money on high performance parts like a Weiand Team G intake manifold, a Magnum 280 cam from Competition, a set of beautiful aluminum heads, Brodix Track I, Holly 750 carb, a performance HEI distributor from a local hotrod shop, gear reduction mini-starter. The heads alone, non-ported were $1400.
The swap kit was a scarab kit and headers from Hooker Headers. I liked those headers, but if I had known about Mike Knell at the time, of course I would have chosen his kit.
My first choice for a tranny was the 700R4, but those things never lasted in my car. Finally went over to the TH-350, burned out about 2 or 3 of them, until my friend got me his bullet-proof TH-350 with a nice shift kit.
The stuff I probably saved money on was getting radiators and shrouds from the junk yard, using Pep Boys or Autozone starters, alternators, brackets, transmission coolers, electirc fans, K&N air filters, etc.. When I broke the half-shafts, going to the salvage yards for R-200's and shafts saved some dough I'm sure. My original Z was a 4-speed standard, upgraded to a 5-speed standard, so when I got the automatic, I used a Datsun automatic shifter from the junk yard.
You need to get a custom cut Chevy drive shaft with flange to match the R-200( I hear they're using R-230's now out of Infinity's and ZX's? ). I also got an aluminum differential mount to stiffen it up a little bit. I got some Tokico 5-way adjustable struts for the rear, which was nice. Lowering springs didn't work out.
Gas costs. At about 10.5:1 compression, I used 93-octane super unleaded, but it could have run on just unleaded I'm sure. On race nights, I would go to this one gas station which sold 100-octane VP racing fuel at the pump! About $2/gallon there, about double the cost back then. Later on, I added a 150-shot of NO2 ($400?), but that was only after everything else was working right. That bottle put me in 750cc sport motorcycle territory!
On the motor, I easily beat Vipers, Corvettes, NOS and supercharged 5.0's, and any other four-wheeled car I came across except for those big-block hot-rods on the spray that had to be trailered out. Even then, I would give them a good run. And if I sprayed? Forget about it...C'ya!!
Just taking a guess, I'd say I spent at least $7,000 directly related to the V8 swap. But that is SOOO much better than paying $80,000 or so for a Corvette or Dodge Viper, being in debt for 4 years, and then getting your doors blown off by a 25-yr old $1900 Japanese import with $7,000 in mods, right? And in front of your wife/girlfriend of the day? hehe
Oh, and don't forget tickets! I had to get a lawyer to handle my numerous citations in court over the years. There's just something about a 400HP pocket rocket that can accelerate from 0-100 in the blink of an eye that attracts the attention of the cops and earns a reputation with them. I probably averaged about 2 to 4 tickets per year while I had the V8.
BTW, is the 280ZX your only car? Do you have an MN-12 T-Bird by any chance? Just curious.