Chad Speier
Active Member
I had huge changes to the port for RD2. So this is a dykem/alcohol test at 36"@.800 lift. Actual burn pattern from the dyno'd engine, cleaned and tested. The rework. That is power found.
Crazy Port Velocity
- Thread starter Chad Speier
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Chad Speier
Active Member
The area with no dykem has no activity. The picture that has that side with dykem is after I tweaked on it again. It now has a more complete burn pattern.
OK, it looks like there was a noticeable change in the port roof vane. Mostly in the direction, but also in the thickness/profile of the vane. The leading edge looks to match the valve guide diameter, then it sharply narrows and widens (between yellow arrows) as it spills into the throat.
Anything else you can share about changes to the port ?
What do you use to add to a port for something like this ? You can't simply grind that into the port, there surely is not enough material at the proper height/location.
Chad Speier
Active Member
most heads you just have to add epoxy and make your own wings. All the changes were done to the front and rear of the guide. That is the only place I concentrated on. I was blown away. I've concentrated on that area in other heads but this small port is a totally different animal.
Chad Speier
Active Member
Chad Speier
Active Member
A guy just needs to be sitting down when you buy them! I have great customers! They were gifted to me. Lucky me!
Chad Speier
Active Member
Chad Speier
Active Member
No, still waiting on cam and rockers.
Chad Speier
Active Member
Chad Speier
Active Member
I believe the TH200 was the forerunner to the 200-4R, they added a 4th gear (OD) and a lockup torque converter. They both have the same gear ratios for first thru third and reverse.
It's interesting that the TH200 went from one of GM's worst transmissions with a high failure rate to a sought after trans for several drag racing classes with it's low total weight and low internal rotating mass.
200-4R
Reverse- 2.07:1
I built the 200-4R trans that is in my TBucket. Every thrust washer has been replaced with a Torrington thrust bearing, so it's parasitic losses are even lower than the OEM trans.
Post #83 and #86 show the machine work for replacing the thrust washers with thrust bearings.
It's interesting that the TH200 went from one of GM's worst transmissions with a high failure rate to a sought after trans for several drag racing classes with it's low total weight and low internal rotating mass.
200-4R
Reverse- 2.07:1
I built the 200-4R trans that is in my TBucket. Every thrust washer has been replaced with a Torrington thrust bearing, so it's parasitic losses are even lower than the OEM trans.
Post #83 and #86 show the machine work for replacing the thrust washers with thrust bearings.
TBucket 200-4R Transmission Project
Omg, I thought I could sling BS pretty good! You two are in the pro category! :lol:
garage.grumpysperformance.com
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