I have a 64 Chevy II Nova with a 347 ci ls1. Right now I am running a th 350 with a 8" converter . I am seeing around 4500 stall on the data log from EFI LIve and it just does not seem to be enough. Yet I am seeing just over 20% slip on the big end.

A little about the car.
the car weighs 2730 with me in it and will be dropping one of the batteries out the back to get about 2660 or so race weight. The car is mostly fiberglass and lexxan windows , rear end is a 12 bolt with 4.11 gears but with 31x13x15 ET drag slicks. I am crossing right now at 6300 rpms at 122 mph so I am thinking of trying 4.30 gears i have laying around to see if it makes the converter any more efficient .
THE engine is 11.63/1 comp. heads are 5.3 heads locally ported with 2.0int 1.60 exh. valves, cam is a 239/243 at .050 with .612 lift 112 lsa 110 icl.

I have talked to a few converter company's and was told to go around 5400-5500 stall since its a race only setup. My thing is , I want to change converters and rebuild the transmission( refresh) while its out.
SHould I just go to a glide while doing this ? Whats the real advantage over the th350 if so?

I want the car to leave hard, right now with the converter in it I am only getting 1.54 60 fts . It should leave a lot harder, I was thinking the 1.3's .

Do the big tires kill my 60 ft since they are a lot bigger then I need? I have some 29x12's I could switch to if needed .

best so far with the car with mis matched parts is 10.80 @122.8 mph.
I am also taking the front facing scoop off and replacing with a 6" cowl up to the windshield before painting to help with wind drag.

 

if you ask me (not a pro) that car does not need a glide. if you feel its not strong enough you could always go up to a th400

 

At your power level I am 100% sure a glide will slow it down.

You need a better converter, you shouldn't see that kind of slippage. Also with your tire height, that's not enough gear. If you have a set of 4.30's you can slap in it I'd do that immediately and see what that gets you, I wouldn't be surprised to see it need a 4.56 with that tire height. Hell I know guys with M6 setups that are running a 30 inch tire with 4.71 gears, that being said get the 4.30 in there, if that helps, buy a set of 4.56's and put them in. See what that gets you, then change the converter. I bet the gear change alone will probably increase the converter effeciency by 5% if not more.

A 5500 converter with about a 9% slippage would be perfect.

I'm not austin coil by any means... but try that path of changes and I think you'll see a really good gain.

 

Those 29" tires and the gear change to the 4.30's ya have.
P.S. nice racer there.

 

using tci converter slip calculator i come up with 13.8% for your set up.

 

You don't need a glide, the car isn't leaving near hard enough to need the step down in first gear ratio IMHO. You need more gear and/or less tire height plus a better converter.

Derek

 

i had a NA 346 that i ran a 4.30 gear and 28inch tall tires.

you need wayyyyyyyy more gear or less tire.

and at that power level you want that big 1st gear ratio so i would not put in a glide

 

Thats what I thought to. If it dont rain this weekend I am going to the track 1 more time to see what it runs after a ported throttle body (coming from a marine tb that is smaller throat then stock but stock size blade) and removed a 70 lb battery.

I was also lean all through 1st gear last time out so I am going to try adding fuel below 6000 rpms with efi live.
1st gear was 13.6/1 and 2nd and 3rd gear were 13.0/1 . It needs to be a little fat below peak tq and lean above that so I am going to play with the tune some before making to many changes. After that the gears are going in. IF they do good, I am putting the 29" tires on to see how that does.

Thanks for the advice.

 

have any of you ran a 325x50x15 drag radial on a 12 inch rim? I am going to try the tires before the gears and then try from there the drag radial and if a 28 inch tire, should put me where I need to be in gear.

Or go with the 315x60 with the 4.30 gear. I am thinking about using the Hoosier drag radial instead of the mickey T tires.

By going with the shorter tires I can lower the front more and set the whole ride height down a bit to help with wind drag. I should hook fine on a drag radial untill I really step up on power. Not looking at doing that for a while since I really just want to run low 10's.

 

No expert here, but I agree completely with this statement.

I think it's in the combo that you're running. I would say go w/ smaller tire and a larger converter... somewhere in the 5000+ range.

 

I am going to get the converter redone after I find out what it wants gear wize. I talked to BTE about redoing it after I get every thing else lined out. One thing I am waiting on is the new Edelbrock Intake when it comes out. IT may like more rpm and need more off the line so I want to do it once.

 

Next wheel/tire combo I go with will be a 325 radial on a 12 inch rim, all the research I have done says that should work better then putting them on a 10 inch rim, by far. I'd try that, only problem is that a tire that small will look out of place on your car, and you'll have to adjust the rear ride height alot for a tire that much shorter.

Try the 4.30 gear, and if that works, I'd get a set of 4.56's and put them on there.

Old racer I know always told me run the biggest tire and the highest rato gearing that will fit in the car, and it will always leave harder and be more consistant.

 

well the car actually sits down a little now in the back and I have coil overs on front that have a lot that I can go down. By going shorter on the back and then setting the front down to match it will actually put me lower to the ground which should be a good thing. I know that if I ever put a big motor in then I will want the big tire back on there but with this combo I think the tire can go down a little .

I have a set of 29x12 Hoosier slicks that are going on to see how that does and then I will put the 4.30 gears in.
I found today that I have a bad tube in one of my slicks so since they have to come off , I am going to try the smaller tire first.

I leave in the morning for a week for work, when I come back I am going to make the changes to get it lower and the other tires on. Allign the front end back up and go race.

I will bring this thread back up after with the results.

 

several years ago when i was running low 11's with my 3200lb street car,we tested a th350 vs th400 vs glide,car started with a th400 running 11.20's,swapped out to the th 350 and run 11.10's,finally switched to the glide and went 10.80's,same converter in all 3 trans,car picked up 60' and mph.
We did this test during the course of a 2 day period at the track(what a pain in the *** but .4 was well worth it.

just another perspective

 

I have been getting that a lot by local guys to put a glide in it. I am going to try that later for sure. I am going to see what i can get with the 350 th first.

Thanks, guys

 

I think a car under 3000 lbs can benefit from a glide. But that is a big tire. I would like to see the two trans tried under same conditions. I think the glide with more gear. If you put more gear in the car you may not see a better 60 with the 3 speed if it trys to spin that is for sure when you need a glide , but now i say do the tires if it helps get some gear and run the fat *** tires. I love the old cars with fat tires. Also is that a steal hood

 

How much of the gains were weight related do you think? That same test, but adding ballast over the tranny (so the weight was in the same place for accuracy sake) would be a really nice test, to see if the weight of the tranny's was impacting the results.

I wouldn't be surprised to see that be a substantial factor.

Every car is different though, and until you have tried it never rule anything out.

 

We swapped back and forth from glide to th350 back to glide same test session with 2 different convertors in both applications in a 3050lb. car. The glide was quicker by as much as .45 and as little as .35 better compared to the th350 in the 1/4 mile.

The 350 is more fun to drive but the glide was quicker and more consistant.

 

Really. I'm not throwing the :BS flag at what you're saying, but that's a big difference to see, how did the car 60 foot with each tranny? Was it blowing the tires off with the TH350 and then started hooking with the glide?

I know they take less power to turn over, and weigh a good bit less just trying to figure out the rest of it.

You guys are making me want to swap to a glide now. Thanks LOL.

A glide question: anyone see that TCI glide on the back of the national dragster? The one that has the electric pump to circulate the fluid when the car isn't running? Anyone know of someone that's tried that, or is using one? How is that working out? Seems like a good idea, but I'm not sure at what point that's needed....

 

I say put the 29" tires on the car.. Go up to AT LEAST 4.56 gears and put the glide in it with a 5500 converter. Or keep the TH350 and go to the smaller tires and a little bit more gear. Definitely need a looser converter though no matter what trans you decide to use.