cleaning up the slant six head
So to add fuel to the fire, since the heads flow was clearly designed for the small cube 170ci and not the 225. Would it be more profitable, if building a NA slant, to build a 170ci instead of the big 225?
I realize the 225 to have a torque advantage, but I imagine the peak hp levels would be similar.
Either way, I'm in the process of assembling a Hyper Pack 170ci for my '64 Dart. The dart is going to be a fairly period correct gasser but with a 170ci slant and a 4spd. Not going for fastest car, but Im hoping it runs in the 14s.
What do you think?!
I think you MIGHT be able to get it into the fourteens with a 170 if you put that Dart on a diet and get a 4-speed behind the motor, and outfit it with the right tires and gears.
Here is a picture of a friend of mine's Hyper Pack 1961 Valiant taken in about 1963. It was a 225, and didn't have the 10.5:1 pistons... he had, instead, milled the head .100". Everything else was regulation Hyper Pack..The car suffered from traction issues with the tiny 13-inch tires, and the gear ratios in those early Mopar 3-speed manual transmissions were pretty awful... kind of like a 4-speed that was missing 3rd gear.
He had the car at the strip a lot for about two years. His best time was a 15-flat at about 93 mph.
I can't imagine that a 170 would come anywhere close to that without fixing he transmission (ratio) issue and gearing it in the basement with some 4.56 gears and a pair of slicks.
A 4-speed would fix the tranny problem, and an 8.25" rear (or, an 8.75") would ne probably a really good idea, as the little 7.25" rear won't last long with any kind of bite.
The right clutch may be out there, but it will also be something to spend a lot of time researching, because this is going to be a low-torque, high rpm motor and you'll probably leaving the line at over 6,000-rpm... hard on clutches.
One of the Ramchargers (Pete McNicoll) had a 170 slant six in a '40 Willys coupe at the NHRA Nationals at Indianapolis in 1961 or, '62 (or, perhaps both years.) He literally dominated that class... none of the other 6-cylinders could run within a train-length of him.I was there, and it sounded like he was spinning that thing about 8,500 rpm. 170's will do that...
The fact is, though. a 225 is 33% bigger to begin with, and that is an insurmountable amount on the street to make up....
It's a GREAT race engine where they classify cars by dividing their weight by their engine size (cubic inches,) but in the real world, size matters...
The smart money is on the 225.... There's just no reason to try to do it with a 170 unless you're class racing (where the 170 has proven to be virtually unbeatable!) or, just trying to prove a point. The 225 slant six has almost no value in the automotive aftermarket/junkyard-world; people give them away all the time... If it were me, I'd replace that 170 short block with the stroker 225 and enjoy the extra 55 cubic inches... But, it's your money; spend it like YOU want to! :)
