Block and head questions

Currently starting my build from a B21FT out of an 84 GLT.
As a bit of context, I am doing an MS conversion with this motor, running some decent flow Holset turbo likely. Completely rigging new fuel, electrical, probably gonna even end up doing MSnS, already aware that I will need a ton of stuff from an EFI system (intake manifold, TPS and pigtail, pos sensors, etc)

Additionally I will be taking the A cam out of a B21A from the 82 DL that I'm building my project up in.

What I'm curious however, is what issues I'm gonna run into with the actual strength of the components I'm working with.

So I have the following questions:
1. What's the weakest link in the B21FT's block?
2. If I'm talking about raw reliable boostability with proper engine management, which will withstand more power, a stock B21FT block or a stock B230FT block.
3. I've heard the flow through the B21FT head is incredibly restrictive. Is the B230FT head vastly improved? If not, which head should I look for to improve flow OR should I just be looking to open up the head myself, and home-rig some better flow with bigger valves
4. What are the weakest links in the heads to reliably take boost, and which head would be my best bet?

For reference to the amount of boost I'm talking, I figured with clean flow, and good engine management, I could reliably make about 300HP off around 20-22PSI.

I'd love to be able to increase that as the future comes, but I'd like to take the process slow.

While I'd rather conserve money while rebuilding the engine, if there's some clear and priority improvements that need to be made (Let's say hypothetically weak piston heads, or shotty connecting rods) to reliably take the boost as a daily driver, then I'm not worried about rebuilding with something stronger.

Essentially trying to build the dream 8V on a medium budget (considering how much MSnS and all new fuel and ignition systems will cost me, I'm not necessarily scared off by price. Just trying to keep it tight).

Thanks,

1. There is no weak link. The pistons and rods are strong but heavy. The can handle the power you are interested in with proper support like good tuning.
2. The B21FT until you get to the rear thrust bearing squirter blocks. That piston cooling helps a lot.
3. These heads should get flow improvement work to make power. It helps a lot with keeping heat down. The heads are basically the same with two main variants. The small coolant passage heads are the good ones. The large coolant passage heads should be welded to reinforce them for high boost. As far as flow the 405 heads and the 531 have larger ports and flow slightly better but a 530 head that is worked on is going to do the job as well.
4. Read this article. https://forums.turbobricks.com/showthread.php?t=163335

That amount of boost has been run on B21Ft engines with the stock kjet injection. Back in the early days here people ran 20-22psi on a B21FT usually with water injection and extra fueling mods to the system. Times have changed and to do that now I'd change it to efi.

You can reinforce the stock rods by having them shot peened and the pistons can be coated to0, but I'd buy the H beam aftermarket rods and aftermarket pistons to really lighten up the load on the crank.

Any links to where I might find good aftermarket rods and pistons?

If I find a B230FT block with Piston Squirters, that's the preferred long-term reliability build?

Also, if I'd hypothetically asked about 400-500HP, lets say like ~30PSI-33PSI, how would your answers have changed? Just getting a scalable idea. May never go there.

Read & Weep.

http://forums.turbobricks.com/showthread.php?t=271886

You can check out stuff on yoshifab, Deeworks, STS machine, and Classic Swede. Of course if you don't mind shipping there is a huge world of parts for going fast overseas. KG trimning, KL racing, just to name a couple.

Yes, but you can add squirters to any red block. Using this rental tool kit. https://forums.turbobricks.com/showthread.php?t=115422

More upgrades to the flow system through the engine. Larger intercooler. More headwork, Bigger cam. Custom intake and exhaust manifolds. High flow fuel system. A drivetrain up to the task. Probably OK with the stock rear if you don't abuse it much and it's a 1031.

Sweet. Looking forward to bringing this project to life. Thanks guys