Twin Turbo 1971 Scamp Project
I think the slant suffers from the lack of a cross flow head and a 4" stroke for hi rpm use. That being said Hyperpak 170s revved really high in the early sixties NASCAR series they ran in. My daughter's 71' runs incredible for a normally aspirated slant. I think if I wanted 220-230 rwhp I'd stay with the slant cause we've done the build over and over. You weren't happy at low 13's either but in the 80's we would be jumping up and down at that street performance!
If my car was a complete V8 car I would have done something similar to your build. Tim's yellow turbo Dart for sale on this forum is amazing as I ln
know the car real well. Outside of an LS I gotta go with the LA engine for great power potential.
The more quick street A Bodies we have the better IMHO!
I want to represent our cars at some of the import events to keep our youth interested in the beauty of our cars. I think this is a point that some will overlook. My interest in certain cars was driven by what I saw winning at the races. Cool part about what we do is that there is more than one good way to build a hot rod. Your last bit of Americana is on forums like this!
Everyone should love the fact that my teenaged daughter loves her Plymouth Scamp and her Dad has one right behind it!
Next time I head to Bentonville we should both head 90 miles and meet up in the middle Bill! Wal-Mart is a customer of ours.
Dave,
The problem as I see it, with the slant six cylinder head, lies not with the lack of a crossflow port orientation, but with the valve size limitations imposed on it by the small bore size.
A 225 slant six has the same displacement per cylinder as a 302 Z-28 small block Chevy, which comes atock with 2.02" X 1.6" valves.
The Chevy has 5.21 square inches of valve area to service the same displacement that the /6 has to try to feed with 4.16 square inches when using the 1.75" X 1.5" oversized valves most builders use for hi-po /6 heads.
That's a difference of 25-percent!!!
With a handicap like that, it's no wonder that it's a difficult battle to get meaningful hp/cu,in, numbers out of normally-aspirated slant six motors.
In all honesty, I don't think that a crossflow port orientation is going to help much, given the problem with valve sizes.
The fact is, the head was designed for the 170 and was never changed. There was no room for bigger bores, so when they needed a displacement increase, they just stroked it (an INCH!!!) and that gave is a 25-percent larger motor, but with the same-size ports and valves.
On the street, yes a 170 will rev to the moon, and in pounds-per-cubic inch classes, the 170 is a KILLER, but it's just too small to make sufficient power to haul a 3,000-pound car around with the kind of musclecar performance most folks are looking for in a street bruiser.
GuzziMark got great performance out of his normally-aspirated 225 by putting his Generation I Valiant on a severe diet and runs some impressive numbers with that car, but not everybody can get their curb weight down as low as he did (2350?)
He also has run the engine on N20 with great success. He holds several records with that little rocket!
Another way to go fast with the 225 is to employ forced induction (super-or turbo-charging) which can be fun, also.
Not really cheap OR easy, adding a turbo to a slant 6 seeems to make an end-run around the built-in breathing problems these engines seem to have.
You pays your money and you takes your choice!!! :cheers:
