TH 400 1st gear?
 

Been "advised" much concerning correct 1st gear needs for my 3500 lb car with 5.14 gears and 30" tire, behind a decent BB chev Stocker and TH 400 trans. Any "rule of thumb" I should be using?

Re: TH 400 1st gear?
 

You didn't say if it's a Stocker, S/S or bracket car but the stock 2.48 is a good starting point. Keep in mind that we're racing at least 1/8 or 1/4 mile and not just to the 60'. A close ratio trans may result in a slower 60' time but due to less RPM drop on gear changes, could result in a quicker E.T. On the other hand a trans with a wide ratio, say a 2.75 for example may provide a quicker 60' but may fall down too much on the gear change. Converter stall also comes into this discussion as well.

Re: TH 400 1st gear?
 

Says BB chev stocker

Re: TH 400 1st gear?
 

Have been told about the "fall Down" several times. Converter is a ATI 8" set up pretty loose. Haven't run it yet but anticipating a flash of around 5800-6000 rpm. I wish cost wasn't an issue, but of course it is......making the mistake on the ratio is concerning. Have been looking at the Coan LW 400 with the 2.48....and comparing with same trans with the 2.75. any way to determine existing trans 1st ratio? It's a Kilgore deal, recently freshened locally, but the trans guy said he couldn't tell and Kilgore "couldn't" locate original build paperwork.

Re: TH 400 1st gear?
 

What class and combo BBC?

Re: TH 400 1st gear?
 

70 Nova.....B/SA....402", GM 401 Alum Head

Re: TH 400 1st gear?
 

Turbo 200 with 2.75 low, swap converter for one for a 200. Put the 400 in a pick up truck where it belongs. The fast big blocks are successfully run in 200s.

Re: TH 400 1st gear?
 

..Or 33.5' Class A 454 motor home, like the last one I built for anything ;-)

Re: TH 400 1st gear?
 

Or sell TH400 to bracket racer, I ran my TH400 for many seasons no issues @ 700hp and 2900lbs.

Re: TH 400 1st gear?
 

so much for defending stock racers as being snobby.....LOL

Re: TH 400 1st gear?
 

That's right . At least I don't have to take them to Camping World ..yet!

Re: TH 400 1st gear?
 

WELL- I’ve never been accused of being snobby before, that I know of. And I have absolutely no idea who Dano is if he isn’t cuffing anybody. I am just trying to to help somebody I don’t know make the correct transmission choice. I think I might be qualified to make that suggestion. You I don’t know about. So you can kiss my snobby but.

Re: TH 400 1st gear?
 

Ding Ding Ding we have a winner. Have it with a turbo spline. BP

Re: TH 400 1st gear?
 

Guys need to keep in mind that not every single stock class racer may be willing to spend $6,000+ on name built TH-200 or Pro Trans that is built to withstand a big block. I've priced both for my own car. I run a lightweight TH-350 in my car and find it hard to justify the added cost vs. the little gain in E.T. Personally, I see lots of other areas where that kind of money could be better spent. One could install top-of-the-line ignition and fuel systems, plus a data logger for that kind of money and probably have a few bucks left over. Just my .02.

Re: TH 400 1st gear?
 

A couple observations about your posts,
1) In your first post, you mention 5:14 rear gear. That's a bunch of rear gear for a car that should hit 125 MPH. You are going to need a really good BBC.
2) You stated that you already have the converter. The converter should be the last thing you buy, built to the finished engine/transmission/rear gear/tire combination.
3) There is a lot more to converters than stall. "K" factor, lock up potential, plus fin and stator design are all factors in the converters performance.
4) If you already have a real Kilgore, you already have an "expensive" transmission.
5) If you are looking at Coan, you are looking at an "expensive" transmission.
6) If your transmission was just open and your transmission guy could not tell what ratio was in it...well to be blunt, you need a better transmission guy.
7) If you have a real Kilgore, he has multiple ratios available.

Disclaimer: These are my opinions and not be confused with facts or snobbishness.

Re: TH 400 1st gear?
 

What's "cuffing"?

BTW, the Snob comment was directed to only one post. To others that were actually trying to help, thank you.

Re: TH 400 1st gear?
 

Not for nothing with the combo you're running you better adjust your budget or change combos. The price of a TH-200 is going to be one of your lesser expenses.

Re: TH 400 1st gear?
 

In response if I may....
1) car runs 122 mph with old converter
2) Converter matched to all you've mentioned
3) Above my pay grade right now
4) This I know
5) Coan is on the way (when referring to "expensive" I consider $ 6500.00 and up to be expensive)
6) You are correct
7) Again, you are correct

Disclaimer: When advised to get rid of my Motorhome Transmission, yes I considered that "snobby". Most of the replies I got were considerate/helpful as yours was.

Re: TH 400 1st gear?
 

Interesting that when told to keep the 400 for a pick up truck, (they did put them in 1 ton ,454 Duallys) , you're okay with that, but a motorhome? That's way over the top
It happens to be true, and just an extension of someone else's point .

Peace brother, and happy holidays.

Re: TH 400 1st gear?
 

Remember sec0nd gear is important in heavy car too. 3600 lb bbc wi 815 hp 2.75 low helped.

Re: TH 400 1st gear?
 

Rome wasn't built in a day...…nor is stock easy or cheap

Merry Christmas

Re: TH 400 1st gear?
 

Coan 2.75/1.56 best I can do right now.

Dan

Re: TH 400 1st gear?
 

Merry Christmas

Re: TH 400 1st gear?
 

Dano, My first reply to you is if your on a limited budget don't worry about being the fastest one out there. Go have fun and see if Stock is really what you like doing.

Now if I was going to give advice as far as your car. The first thing I would tell you is to sell the Nova and find a Camaro. You would be already .15 ahead of the game. Your 5:14 gears are the right ones. If you went with the coan your getting a great trany. Not the one I would put in my car but still a very good piece. One thing I learned years ago always try and go with the best possible parts the first time. Even if it puts you over budget. If you buy less than the best most of the time in a year or two you will be looking to put the best in your car. I just don't like spending my money twice. Good Luck with your project and remember this is supposed to be fun. BP

Re: TH 400 1st gear?
 

much to my wife's chagrin I usually DO try to buy the best, if not just for piece of mind. I changed the gearset on the Coan yesterday. Then let the misses know. Good Times!!

With that being said, I admit that purchasing the Nova was not the best foundation, but I've got it.

I've been racing for many years in the bracket classes and SST through TD. Thought this would be a fun little distraction in my retirement years. LOL!!

Anyway, I appreciate the help I've got from this forum.

Merry Christmas!!