I agree with What Hotrod Lincoln said... if you’re on flat ground these engines and trans are adequate up to about 50MPH. And the whining you hear is due to the cut of the gears as he said. The 420 will have a little whine but nothing like the crashbox. You’ll need to practice to shift the crashbox using the double
Clutch method, only problem with that method is that it takes so long to shift that way your RPM will drop and the 216 lacks the torque to get the RPM back up again. On flat ground and empty, it’s doable, any kind of an incline and it’s a real challenge to upshift.
My biggest issue with the crashbox is downshifting.... I can get the upshifts with a little practice on backroads, but I can’t seem to downshift without grinding. So I’m going to swap in a 420 at some point and a more powerful engine. If I lived on flatland I wouldn’t necessarily “need” to.
1. Is the trans that comes with the 216 geared real high in first gear? Seemed like it, when going up a incline on the back road it still needed speed to get up the hill, even in 1st.
Answer: first is low. Very low, often called granny gear. Not sure the ratio. Info on these transmissions is difficult to find.
2. Anyone who upgraded their engine to say.. 235, 261 or 292.. Did these characteristics change? Like if you change the rear to open rear and go sm420 trans? Does it keep that cool whining sound of the drivetrain?
Many have upgraded, tons of threads here about engine swaps. Anything is more powerful than the 216 and the 261 can be swapped i. And made to look very original, probably fool 99% of people.
2. Anyone who simply upgraded to a 235, did that give the truck enough power to go >50 MPH on the hwy while keeping the axles and rear original
I don have experience with a 235 personally, but the difference in power from 216-235 isn’t a lot of both are stock. But if your talking a rebuilt 235 with cam, head work and dual carbs could be a decent upgrade.
Last edited by Tony292; 11/27/2020 5:00 PM.
