Fix Th400 or switch to PG
Thread Starter
TECH Fanatic
Joined: Oct 2011
Posts: 1,425
Likes: 0
Fix Th400 or switch to PG I am in a predicament. My th350 went out last year and so I upgraded to a TH400. The 400 went out and we fixed it again with a better drum, clutches, et. Once again I am out 3rd gear. So here is my dilema. I can fix my 400 again which is going to about $450. However, I have someone who will give me $360 for it likes it sits. I then have a different trans guy who can build me a PG for $900. So if I sale the trans the PG is only costing $540. Only a $90 difference.
So I am not sure which to go and there is no guarantee I won't break it again. The guy who does the PG's think my car will run faster and the guy who does the 400 thinks the PG will slow it down.
Here is the details:
1969 Chevelle
Weight: 3700-3800lbs
3.42 gears
Tires: I can run 30" or 28"
5.3 with twin 70's, E85 and 15lbs of boost. The 70s have a .68 AR.
Edelbrock Pro Flo XT intake.
PTC 3400. Very tight convertor. Drops around a grand between shifts.
When my car last ran at the track, once it built boost it would hit the rev limiter before you know it. Even from 2-3rd it hits the limiter quickly.
I figured the taller first gear in the PG will allow it to pull longer and harder in first and I am making more than enough power at that time for it to continue to pull when I shift to 2nd gear.
What do you think? Let me know if you need anymore information.
It is a street car but I will give up some driveability to be faster at the track. I would think with the PG it would run better both in the 1/8th and the 1/4.
I can leave on as much as 12lbs of boost so far, but the most I left on with the 400 was 7lbs.
So I am not sure which to go and there is no guarantee I won't break it again. The guy who does the PG's think my car will run faster and the guy who does the 400 thinks the PG will slow it down.
Here is the details:
1969 Chevelle
Weight: 3700-3800lbs
3.42 gears
Tires: I can run 30" or 28"
5.3 with twin 70's, E85 and 15lbs of boost. The 70s have a .68 AR.
Edelbrock Pro Flo XT intake.
PTC 3400. Very tight convertor. Drops around a grand between shifts.
When my car last ran at the track, once it built boost it would hit the rev limiter before you know it. Even from 2-3rd it hits the limiter quickly.
I figured the taller first gear in the PG will allow it to pull longer and harder in first and I am making more than enough power at that time for it to continue to pull when I shift to 2nd gear.
What do you think? Let me know if you need anymore information.
It is a street car but I will give up some driveability to be faster at the track. I would think with the PG it would run better both in the 1/8th and the 1/4.
I can leave on as much as 12lbs of boost so far, but the most I left on with the 400 was 7lbs.
I'd suspect you'll slow down a little with the glide. My car is lighter, but I made the switch to the P/G from a 350 and it slowed me down a little, but I have since been able to make up for it leaving with more boost out of the hole. Driveability I'd actually say is better with the glide, one shift and cruise. I have to leave with 13-15psi to get a low 1.3x 60', I used to leave on 7psi
What happened to cause 3rd to burn up? Did your builder tell you that?
edit:
Meant to say what did you builder tell you why it burned up 3rd?
edit:
Meant to say what did you builder tell you why it burned up 3rd?
Last edited by slow67; Feb 1, 2013 at 12:43 PM.
TECH Enthusiast
Joined: Oct 2012
Posts: 581
Likes: 0
From: Arkansas
You'll slow with the glide. I did the same thing went from a th350 to a glide and it killed it on my single turbo trans am.. stick with the 400. Glides are great but if you don't want to change your setup the 400 will be the way to go.
I prefer the glide, but if all is working right and you are hooking hard, the th400 SHOULD be faster. Running at over 4000lbs, 2.73's, and glide, I've been 1.5 60ft on street tires(not drag radials), so don't let people tell you it's too heavy. If you run on the street or not well prepped tracks, the glide will be faster / more consistent.
Trending Topics
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo Thread Starter
TECH Fanatic
Joined: Oct 2011
Posts: 1,425
Likes: 0
Well...it may go against the norm but I went ahead and did a deal for the glide. If it doesn't work out then I can always go back to the 400. I can now build 10-12lbs of boost where as last year I could only leave on about 3-5lbs and hence why I think it was a dog off the line.
Initially I may be slower but I think with some tuning and sorting I can get the glide to run much faster by eliminating a shift.
Thanks for all the input.
Initially I may be slower but I think with some tuning and sorting I can get the glide to run much faster by eliminating a shift.
Thanks for all the input.
good God! 3700lbs. thats a heavy sumbitch.
my nova is 2950 now and im killing myself trying to make it lighter still.
im in the same predicament. high gear clutch is fried, hub is showing wear. I can put it back together with good parts and sell if for a pg and lose 30lbs or I can keep everything as is and run the 400.
it is a very tough decision. i have heard that the th400s for the same money are stronger than a glide though so im leaning towards the th400.
good luck with the glide. i saw dville gt switch and it did amazing things for his times. also , you just lost about 30 lbs of weight.
my nova is 2950 now and im killing myself trying to make it lighter still.
im in the same predicament. high gear clutch is fried, hub is showing wear. I can put it back together with good parts and sell if for a pg and lose 30lbs or I can keep everything as is and run the 400.
it is a very tough decision. i have heard that the th400s for the same money are stronger than a glide though so im leaning towards the th400.
good luck with the glide. i saw dville gt switch and it did amazing things for his times. also , you just lost about 30 lbs of weight.
Thread Starter
TECH Fanatic
Joined: Oct 2011
Posts: 1,425
Likes: 0
The fastest street car in our area (one that is daily driven at least) is a 69 Nova and he is around 3400 and he runs a PG built by this guy. His car runs 7.0 on motor and 5.85 on spray. He runs 3.50 gears. He has his nitrous come on gradually but leaves with enough to get it to launch. I am hoping I can do the exact same thing with my turbo's.
I can't imagine that if I can get the car to leave on 10-12lbs of boost and run a total of 15-20lbs down the track that the glide won't work or be faster. We will see. The key is getting it to build boost on the Transbrake though.
I can't imagine that if I can get the car to leave on 10-12lbs of boost and run a total of 15-20lbs down the track that the glide won't work or be faster. We will see. The key is getting it to build boost on the Transbrake though.
I love my powerglide for the street. Wouldnt give it up for anything!!! Get the gear setup right and the converter dialed in and you will never go back to 3 gears.
Damn that's awesome! I'll definitely have to try a pg on my next build. Hey wicked, you should post some vids up on YouTube once you get your glide in. Hopefully you can get it to launch like a monster!
On The Tree
Joined: Oct 2007
Posts: 121
Likes: 0
From: Grapevine,TX
I am definitely keeping an eye on this one.
I just swapped my perfectly good th400 for
a glide. My experience with the 400 was mixed.
At well prepped tracks it worked great! At mediocre
tracks not so well.
First gear was just way too much, even with a 3.70 gear
and 32" tires. But my car only weighs 2744 lbs.
What stall converter do you have now? It may need some tweaking
with a glide and that heavy pig.
I just swapped my perfectly good th400 for
a glide. My experience with the 400 was mixed.
At well prepped tracks it worked great! At mediocre
tracks not so well.
First gear was just way too much, even with a 3.70 gear
and 32" tires. But my car only weighs 2744 lbs.
What stall converter do you have now? It may need some tweaking
with a glide and that heavy pig.
