What's the streetability of an ST spec MFI engine?

[RobFrost]

I'm building up my 2.2E to a short stroke 2.3 high compression engine with more aggressive cams. How streetable is an ST spec engine? I was gravitating towards 10.5:1 twin plug with mod solex grind, but Henry Schmidt advised me on Pelican that this compression ratio would be folly. It seems the goals of a revvy engine with this much compression, are not compatible with my desire to have a streetable engine that pulls relatively low down the rev range, due to the dynamic compression being too high. I'm taking that to mean 10.5:1 would only work with more aggressive cams which reduce the dynamic compression at low revs by relieving pressure through the escape of combustion gases within the cylinder when the open valves overlap.

Supposing I do indeed go with more aggressive cams, how unusable is an engine with race spec cams, and is there a balance to be struck whereby the engine still goes all the way up (say 7,500rpm), but is nice to drive daily?

[teenchy]

I had my 2.2T built to a short stroke 2380, 10.5:1 twin plug with mod-Solex grind, but on Webers. I had originally wanted to go with E grind, but was persuaded otherwise. The engine builder, who is not Henry but is someone who has a working relationship with Henry, told me explicitly at the start of the build that his goal was to end up with "a streetable ST motor that can run on pump 93 octane." My gut tells me retaining the E cams might give you the curves you desire, but I defer to those with far more experience.

I suspect gearing may play a part in the usability of the engine. The builder is rebuilding a gearbox for me and is playing with some custom ratios. This has been the rate-limiting step in the build, as the engine is in the car. Should I ever get the car back, I'll let you know how it's working out.

[geneulm]

I think you should build it as you spec and it will be great. Couple a things:

It is hard to get to the as-- advertised compression ratio at 1mm deck. They always come out a little lower, without extra decking. Henry is always very sensitive to the horrible gas quality in CA. They just can't run the compression ratio/advance there.

I have a 10:3/ge60/twin plug and have a similar motor in the works in VA. I may have to run a little less advance.