oxfordarctic

Yeah, the 2.8 flows well with an M50 intake manifold, but the ITB's provide even better airflow which is important when trying to run higher amounts of boost. The internals and block can handle quite a lot of psi and power, but the oem style intakes can't always keep up with the airflow needed. The older BMW straight 6's are great engines, but they don't have a lot of output NA, so boost is really the only way to break even the 300whp mark.

Yeah, the 30 series would definitely be a minimum for this build. I've got a GTX3071R single conversion on my Toyota Chaser which is rated for 650hp max, so probably something along those lines for the turbo would be what I go with. The 2.8 is getting cams and ITB's - despite them being kind of a pain to tune with a turbo setup, and of course the basic upgrades for this build such as mhg, arp head studs, injectors, fuel lines, etc.

Appreciate the input! I'll start my search with the 4x4 axles. Depending on the width, I could probably just swap the whole rear axle, hubs and all, right?

The 620 is just a shell. And as I stated in the post, I know this will be an expensive project but I'm doing it just because I can. So telling me to not "waist money" doesn't help.

Alright, I'm looking to go with a full custom rally build on my '73 620 because why the hell not. Also mostly because I'm using a "free" engine out of my buddy's '97 BMW 328i. Here's the main rundown: - Custom engine mounts and placement (might need to adjust the firewall; not entirely sure yet until we mock up the engine) - Custom trans tunnel to fit the 5 speed ZF - Custom fully independent suspension with loads of travel - Sloppy turbo build based around a Garrett ball bearing; not entirely sure how big of a turbo yet - Basically make a stupid rally build probably making upwards of 500whp on the "incredibly-ridiculous-and-probably-shouldn't-be-a-thing" tune map I know this will be a crazy money sink and whatnot, but that's not why I'm posting here. All I need to know is really a few things and to update on the progress of the build; albeit very slow progress. Thing #1: What steering rack would benefit me most in this setup? Guessing is welcome here, I'm just trying to gauge possible options. Thing #2: Rear end ratios. This poor 620 came with the 4.87 diff and I'd rather not keep it. I'm thinking maybe something along the lines of 4.23? Suggestions on what vehicles to rip a diff out of to frankenstein into this ungodly conglomeration of stupidity. Thing #3: Axles/wheel hubs. Also would like suggestions on what vehicles to tear apart and force onto this idiotic death trap. Thanks for taking the time to give input. If you're here just to see how this ends up killing me, welcome aboard. :frantics: