My Katech 416 update
 

As you may have seen, I spun a rod bearing in the stock block. Picked up a Katech 416 shortblock...

TSP 4 cam 235/239 .627/.624
LOD intake manifold
Wegner cnc heads
Z28 cai
FIC 650 cc injectors

My tuner said its running out of air. You can see the graph flattens out mid 6k. They recommend a Nick Williams 102mm TB and a 4.5" cai.... and my injectors will support e85 so I should get the flex fuel sensor. They feel I should see 40-50 more peak hp.

Opinions welcome.

It runs great and pulls hard... it's an amazing short block.

Nice, likin what it does around 5300 rpm, kinda looks like a light shot of something the way it ramps up like that.

Needs a different cam


You picked up some nice torque and man that torque curve is flat.


Maybe a TSP LS7 3.2 cam would help


It needs a lot more exhaust duration, Its taking in tons of air but can't get it out.

What exactly are your goals for the car?

How exactly will you use the car?

KW

What was run one (red lines)?

Red lines are stock ci and factory injectors. That's all that's changed. This was not a planned build. I spun a rod bearing and Katech was the only place I could find that had a good short block on the shelf. I drove to Detroit, picked it up and took the heads cam and intake off my motor and dropped it in the car. Funds were not available to optimize the build.. ie cam change.

Its just a street car....my goal was to have a reliable street car that makes good power.

Well.....you got a street car that makes real good power, and it should be reliable.

I wouldn't be concerned at all about the HP curve flattening out at 6500 RPMs and long as you're not gonna be trying to rev past that point.

Down the line, I might invest in some PAC-1204x springs JUST IN CASE the flattening of your HP curve is valvetrain (springs) related.

KW

This!!! This setup with the LOD should run up to 7000 pretty happily with the right camshaft. I guess it depends on what your goals are for final power, but getting up around 600whp should be pretty reasonable to accomplish with a still strong bottom end and decent street manners. 15-20* more exhaust duration for sure is gonna make more power and run upstairs. Throttle body is definitely going to help as well.

I agree with acammer that you might need more exhaust duration to help let the air out on the top end. If you go that route, it seems like GPI has the most aggressive grinds these days with >250 degress on the exhaust side. The SS3 or one of the SS4 cams would make it shine.

Throw in the bigger CAI and the NW 102 TB and you'll be breathing great. And of course the flex fuel sensor will help too.

Way to make the best out of a spun bearing!!! Very happy you're up and running stronger than before.

Definitely can't go wrong with the GPI guys. I would call and work out a custom grind for your setup - a stroker may have enough of a difference in what it really likes to warrant something custom. Those GPI proprietary cam lobes are fantastic!

Glad you are happy with the shortblock!

What size headers are you running? This could also be a bottleneck. I am in the process of building a 416 for myself, I look forward to comparing our numbers.

-Zach

1 7/8 long tubes, to 3" with spintech mufflers... h pipe. No cats.

Watch "Katech 416" on YouTube
https://youtu.be/4vhcdUHBa7s

Sounds healthy! I definitely think there is some room left on the table as far as power goes. Have you considered bringing the car back over to Katech for further assistance?

You guys have an awesome facility and a great bunch of employees. Very helpful when buying the short block. Unfortunately it was a 17+ hour round trip.

I'm very happy for now... gotta pay off the short block... hope to make some changes this winter.