Type-I in teener?, Why not? Options

[D1A3]

Watched RIDES tonight on INHD and it was all about the 550 Spyder replicas. While I was watching, I started wondering why we could not put a high performance Type-I engine in our teeners.

What are the limitations? Any reason people are not doing it?

BTW, I did search for this in the archives and did not come up with much...

[DBCooper]

The exhaust direction has NOTHING to do with how much the head will flow. That piston's coming up and the exhaust is going out whatever direction a valve and port lets it, doesn't matter up, down or sideways. The problem with the T4 head flow out the bottom is that the exhaust port is between the pushrod tubes. You can't put a huge exhaust tube onto it, like you can a T1, everythings got to be squeezed through a relatively small orifice. The aftermarket T1 heads are different castings and have almost no limit on exhaust port size, so they can flow much more than even a highly modified T4 head.

The head differences affect how much total power you can get from an engine, but when you're talking about putting a T1 into a 914 the important difference is the relative overall strengths of the two types of engines. Look at a T4 crank alongside a T1 crank, the T1 looks like a toy. Compare the size of the T4 main bearings to the T1's. Look at the size of the rods, the quality of the T4 aluminum case. A stock T1 magnesium case will pound out main journals so consistently that most builders automatically align-bore T1 cases when they come in, if they're even still usable. That's not a problem with the nice aluminum T4 case from teeners.

The T4 engine is just stronger in every way, meaning it can push a (relatively) heavy 914 around and be thrashed far past the point that a T1 would start puking oil. It might not be as easy to reach the peaks of horsepower that a T1 can get to, but it can hold on to and keep making the power it makes a heck of a lot longer than a T1. That doesn't mean a hipo T1 wouldn't work in a 914, just not as long. Heck, you can get 300 hp from a Honda Civic or Ford Focus motor, just not for very long at a time. But you can get 400 hp for years at a time from a Chevy V8, no problem. It's built for it. Same thing T1 vs. T4.