All the info you need is here. Read the stickys
The RB25DET head flows way better than an RB20DET head. In fact the RB25 head flows the same as the RB26 head.
The budget skyline block to get (for the money) is an RB25 and you can always go on the differen't skyline forums and come across a used set of RB26DETT pistons crank & connecting rods. They all drop into the RB25 which then intern strokes it to an RB26 block. Now you basically have the same engine minus the quad throttle bodies. All the RB26 head items fit as well.
The RB25 block is NOT the same as the RB26. The RB26 is a differen't casting and is stronger. I doubt this will effect you unless you're shooting for a 1000HP or something.
Going out and buying a Supra does not even compare to a Nissan S14 setup. They're wayy heavier and even with adding weight to the rear of a 240SX it would still be lighter. Not to mention Toyota parts are more exspensive than Nissan.
I do think the RB setup will be more exspensive in the long run 6x parts compared to 4x. Esp for a rebuild.. Getting parts are not too bad but I have a friend in AU so things are much easier for me.
Off subject of what you're asking for:
If I were you I would stick with the KA and go turbo with a rebuilt block. It will be a lot less exspensive and it's 2.4 compared to 2.5.. Granted the 6x cylinders will spool the turbo faster but performance for the money. KA is plenty fine. I like how the torque numbers stay with the horsepower numbers or even excede the HP numbers. Unlike most SR's from what I've seen with 550HP and 410Ft Lbs. It does depend on your tuning skills but torque is what you feel and I need that.
"Mechanical balance. As long as the KA doesn't sit at 7,400rpm all day, there's not an issue. The displacement is enough that the engine doesn't need to rpm to make power so it's not much of an issue. For those who are worried, spend $1.5k to get a custom full counterweight crank and machine the block to clear the crank. That's the KA's weak spot." -'97 S14 SE Turbo
I have the Sport Compact issue May 02 Vol. 14 No. 05 where they weighed the SR20 and KA block.
SR: 490 lbs
KA: 493 lbs
Was this a mis-print?
Gold plated toilet with platinum fittings. I'll take it!
