@GreasySideUp posted:Wow. She runs really, really well. So good in fact that I’m debating if I need the new engine. I put 60km on her today, I have no idea how many miles that is but she pulls a lot better than I thought. I smoked 2 minivans and was neck and neck with a Lexus RX330.
My question now is this. Is it more fun to drive a slow car fast or a fast car slow…. Hammering full throttle to the floor and squealing around the turns on these skinny tires is a blast. I think she may have more than a 1600 under there. It looks like there were a lot of 1915’s put into the Vintage Speedsters. I wonder….. do I need 180hp? I’ve got a huge grin with what I have…. Is more better….?
What I know for sure is that this car is super fun. Exactly what I need in life right now.
I’ve got a few loose ends to wrap up. Tach, temp gauge, turn signals and front running lights. I need to start researching suspension and a steering box as well. She has a bit of play in the wheel. It’s fine at 45 but at 60 I’d love it to be a little more responsive.
More is always better! 
(think big evil laugh here). As you said, the car is "super fun" and the stress breaker you "need in life right now". Any 2 literish (or bigger) type 1 engine with decently ported big valve heads (and the cam/rocker combo, carbs and exhaust to support them) will make at least 140 and maybe even as much as 160 hp, all in by 6,000 rpm, be a torque monster and still reliable as all heck will be a blast to drive in your car. What you will notice, though, is the rear will now come around even easier (you'll be able to spin the rear tires at will) and could use wider rubber (which you may already know is not easily done) to keep all that sliding and spinning to a minimum. One thing leads to another, so it's a slippery slope (in more ways than 1)- watch what you wish for
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Re your front suspension- it might not be the steering box. Exactly what you're describing can be caused by not enough caster. My apologies, I don't remember specifically- are there caster shims under the bottom tube? How (and how much) the front is lowered can really affect caster and make a Speedster quite unsafe even at legal highway speeds if not compensated for. I have been guilty of this as well and seriously scared myself once before I knew anything about front suspension geometry and how important caster is to a car's high speed stability- a bug lowered with just a Select-a-drop and 135's is crude (and downright dangerous) by today's standards. Any VW based car needs at least 3° (stock) caster; if you will never (ever!) take your car even a smidgeon above legal speeds (not even for a moment- "let's see what this thing will do" can have disastrous and very final consequences in a heartbeat) then you could arguably call it enough, but any playing at and above those highway speeds (even for a moment) and your Speedster requires more caster to be dependably responsive and relatively safe (well, there will still be the nut behind the wheel, but that variable we all have to contend with!). Pretty well everyone here agrees that 5° is the minimum figure to look for.
356's came with a very similar front suspension (really early cars actually used VW king&linkpin spindles/trailing arms), were built with 5° caster and were more stable and predictably responsive at higher speeds.
Hope this helps, and Yoda out- time to go back to bed it is!