I just purchased a 68 RS roller. I’m looking at doing a protouring car that drives like new but has all of the looks that makes the Gen 1 what it is. I’ve driven a 2011 2SS with 405 HP for years so that is my gauge on what I want it to drive like. So my question is which size engine do most of you suggest with that in mind? I’m leaning toward something putting out mid 400s to low 500s that I can drive everyday. I want to pair it with a 5 or 6 speed. Is a 396 or 427 the best opinion? I’ll probably buy a turn key crate engine from Jegs, summit racing or other distributor but I was curious on what I should start looking for. Thanks in advance.

 

Well those big blocks can be very reliable with a mild build but they drink gas like there's no tomorrow and they're also pretty heavy.
I'd be looking at an LS swap since you are going pro-touring rather than stock and you aren't butchering an original numbers matching car so why not go modern.
Then you can have both power and gas mileage along with reliability plus the six speed could be sourced along with the motor from a Camaro or Vette etc.
You can buy everything needed for the swap including headers made to fit.

 

As suggested, most any 4th Gen LS engine/trans combo.

 

I know doing an LS swap is really popular right now but I was thinking about going with simple mechanical power. What other opinions do you suggest?

 

Well I guess a small block 383 stroker crate engine would be a good option if you must but it's pretty hard to beat an LS swap for reliability and fuel mileage.
That and the 6 speed option as a package.
You could spend a lot more going with a carbed gen 1 SBC or a BBC especially if you want to adapt a 6 speed and you won't have the weight savings or mileage.

 

Here's a good choice for a big block... https://www.summitracing.com/parts/nal-19331572

 

Well that's a beauty for sure but holy cow over $11,000 before shipping and possible taxes and you'd still have the rest of the drive-train to do.