Premium 91 octane fuel is fine with me.

You mentioned DCR, what is that? I’ll guess dynamic compression ratio?

I won’t be ordering any parts until the block is hot-tanked, crack checked and inspected by my machine shop. I do have a dial bore gauge, snap-T gauges and a caliper set , up to 6”. I measured stock 4” bore,
.0005 out of round, .001” taper. Bores look good. No top ridge to catch your fingernail on. I suspect this block will be going to .030 over. Yet I’ll let the pros tell me that.

I am ok with a forged crank but it might be overkill for me. No racing. I doubt I’ll be going crazy on the throttle often. I am 55 and funding this build. I’m going to bias toward caution versus high revving. Yet things could get a bit spirited, if this car is killer fun to drive.

I am hearing great things about the high-end Scat cast crank. Cast hyper pistons are likely fine for me, but I’m not against forged either. Perhaps a bit of an overbuild is better. Forged crank and pistons are not off the table.

 

Modern high performance engines use hyper pistons for longevity and cost. They also have very precise computer controlled fuel and timing control. Think of forged parts as “insurance” against the not always perfect control of carburetors and distributors.

Since it’s your money I’m deciding on, I say go for it!

And yes, DCR is dynamic compression.

 

The thicker your cylinder wall is, the more stable it is, the better ring seal is, and the better heat transfer is.
IF bore cleans up completely with only +0.020" cut; suggest don't bore +0.030", when a suitable +0.020" piston is available.
With correct wall finish, and within reason, thinner ringpaks offer greater conformability and better sealing; better efficiency.
Let the OE trends serve to guide such decisions.

Don't get so wrapped up into DCR what-ifs; it's a rather inexact, if not speculative tool. Most such programs have little to no CFD input.

 

Obviously forged pistons better, but for a lower compression, 6000 redline 383 you should be fine. Avoid any cheap "claimer" style hyper pistons . Maybe $600 upgrade between hyper and forged but you can sleep better at night if you go forged. 383's are biased to that below 6000 RPM range anyway. Avoiding detonation and being careful to keep wide ring gaps will make it safer with hypers.

Head choice and cam choice will matter a lot to piston choice. Most likely you will need a dish piston to keep the compression down here. A 383 will build a lot of compression with the most common 64cc head. Bigger chambers or dished pistons or both will be required if you want to keep the lower compression. A flat top piston 383 at zero deck and a .040" gasket will be at 10.7 CR with a 67cc head. 64cc is even higher C/R.

I LOVE compression personally, Get the cam right to match the application and the and the higher compression is your friend. Makes for a snappy pedal, more torque and higher efficiency. Mine barks real good when you tap the pedal and pulls hard from right off idle and up. Lower compression will be a bit lazier and not as responsive at lowest RPM. I needed a custom cam to do what I was trying to do.

I would not upgrade to a forged crank here. Not worth the cost at all. Spend the money on a custom cam.

 

Cam choice will depend a lot on gearing.
But 383s will tolerate lazier gearing better than a 350.

Q: What rear gear & trans?

I am very "pro" DCR for the vast majority of people who do not build engines every week.
It avoids having to go deep in the weeds on cam timing, and tells you if you have too much static compression for your small to med cam (ping city),
or the opposite, too big of a cam for a low compression engine (lazy throttle). It is very easy to go too far in either direction. Keep DCR in the high 7s to a max of mid 8*s and it will run great. That can be done with anywhere from mid 8s to 11:1 static CR with different cams. The throttle is much crisper in the 8s. Low 8s is still safe for pump gas.

I put 4 cams in my 11:1 350, so I know what both extremes feel like as well.