I occasionally run mine on the freeway as far as a 20 mile trip, even cruising at 3500 rpms, it's not bad, mileage is around 16 mpg at that speed/rpm (around 75/80)
Toured the Prestige Motorsports shop today and talked to the owner about a potential 347 build. Nice shop, clean with six or so interesting cars getting various improvements. Biggest question on my mind (other than whether to spend the money or not) is about the heads. He uses Dart Pro 1 195s in the standard build but I'm wondering if for my application the 170s would be better. Would the bigger valves and ports in the 195s hurt driveability on a 347?
I would think they would to some degree, but you should have asked them this question. Camshaft grind, intake style (single vs dual plane) carb selection (mech secs vs vacuum plus cfm rating) also affect the rpms operating range to variying degrees. With bigger heads, you'd want to go more conservative on the cam grind. Ford did this with the 351C 4 bbl motors (with the exception of the Boss 351) These motors had huge ports and valves, but really small cam specs, I'd gather the smaller cam grind was to make em more streetable, which in my experience they were no slouch on the bottom ends contrary to what's commonly said about them. My brother had one in a 71 Torino backed by an FMX and a 3.00 rearend. Sure, it could have been lacking something on bottom, but it never felt like it to me.
I expressed concern about the 195s and think I may have talked him into the 170s. He was being flexible and is eager to build what I want and he wasn't sure how much we'd be giving up by going to the 170s. After I got home started wondering if I'm being too conservative so I put the question to you guys. On a 302 I think the 170s might be better for me but wonder if the 347 would handle the 195s OK. Yes, dual plane, vacuum secondaries, and cam for smooth idle. Good point on the Cleveland 4 BBL.
