96Formula6spd

iTrader: (7)

So I may end up with a very cheap 83-85 rx7 that is a 12a car. Of course the engine is toast and the car is heading to the crusher. So I am throwing out an idea for a lechump car build.

So the idea would be to take a 5.3 out of a truck and mate it to a gm nv3500 5spd. All this could be had at pick and pull for the lechump budget of a $500 car.

So the 5.3 part has been covered pretty well. Make some mounts and wire it up to the stock computer. Make what we have work on a budget. The big question is the transmission. Normally on a big build like this a t-56 would be a no brainier. However any lechump judge will say no go. So the idea is a 4.8 trucks engine 5spd which is the NV3500. Seems it would hold up to a stock 5.3. Make some shifter for it and a custom mount for it. Not the most common swap but hey would fly under the radar. Then just run a stock 5.3 for the race. Should be reliable enough.

So my questions are. How do the NV3500 hold up to a lot of shifting and maybe some hard shifts. Anybody know how the shifter hole compares to something like a t-56. Anybody think it would hold up or even work. I think it would be ok for some racing.

Got any ideas. I think it could be done under the $500 rules with some pick and pull prices.

Boneyard buick

Go T5 before you go Nv3500. I had one and they are geared super tall, not the greatest for fast shifting IMO

96Formula6spd

iTrader: (7)

I dont think a t-5 would hold up to a stock 5.3. I know people blowing them up behind a stock tpi 350. Gearing could be fixed later with a rear end change. Hello 8.8? Watched a few 0-100 in some trucks. 3rd is long. But this will be in a much lighter car. Are the NV3500 really that bad?

Boneyard buick

I don't think they're bad, just not a suitable trans for the application.

If your just running a stock 5.3 I would give the t5 a shot, or see if you can find a World class T5, they were a little stronger apparently.

pdsq98gt

I personally am not a huge fan of the 3500 also. The t5 is so much easier to work on. I think they hold about the same amount of power. The input shaft bearing loves to take a dump on them and you need a special fixture to reassemble the case, pita.

96Formula6spd

iTrader: (7)

Any other options to go with. I know its going to be the fun of bolting it up to a ls1 motor. So a t-5 would need a bell housing to bolt up. Any other ideas. Being a lechump car I would need to last anywhere from 12-24 hours of constant driving. Ideas?

By the way here is the one blurry picture of the car I have right now.

Forcefed86

iTrader: (4)

I'd look at a 4.8 instead for the higher reving capability and throw a $90 OEM zr1 cam in it. Will make more power than the 5.3 rev much higher, and still be cheap. 4.8's are valued less than a 5.3 as well for an added chump car bonus.

Do the chump cars require a manual? I'd throw a stock powerglide in and call it a day...Glides are also bullet proof and dirty cheap in stock form. You'll **** off alot of racers with that combo!

ss454327

iTrader: (10)

The NV3500 can hold much more than a stock 5.3 has to offer. The gearing won't be perfect but for a chump racer it should be great...I second the 4.8 option also. You can probably find a 4.8/NV3500 combo easily.

96Formula6spd

iTrader: (7)

Not going to cam the engine. No budget for adding springs and such. Would like to make it sound stock. 4.8 vs 5.3 cost is about the same. So would rather go with a 5.3. Plus they seem to show up more in my local pick and pulls.

As for the transmissions I have not seen many automatics last long races. Yes a powerglide is simple and cheap. But would rather have a stick shift.

Would rather have a 5.3. Yeah gearing is not important. Need to be at the at hour 23 to go for the win in hour 24. Gearing might help. Stock rear end in a rx7 is either a 3.9 or a 4.1. So poor mans supercharger is already there. Bad gearing might help up the gas mileage some. Chump car rules make pit stops 5 mins no matter what. So less fuel stops are better.

i r teh noobz

iTrader: (4)

How much shifting is involved in a chump race? With a high-revving 4.8 and a light car I'd expect that most of the race could be run in 3rd. A T-5 might live if you aren't shifting it hard.

GM full size light duty NV3500 ratios from the wiki:

4.02
2.32
1.40
1.00
0.73

First gear would be entirely useless in a car that small with a 4 something rear end.

My 300ZX can hardly launch without cooking tires with a 5.3, 3.7 rear, and a 2.89 first.

96Formula6spd

iTrader: (7)

Mostly its an endurance race. So could run 2-3-4? 3-4? Use the torque of the motor for the most of it. Rear end is a 3.7-4.1 depending on the model of the rx7.

rotor vs. piston

iTrader: (3)

I had a FB w/ a "350hp/350tq" crate engine w/ a WC T-5 behind it and held up just fine straight out the junkyard, no rebuild.

I had a NV3500 to put in originally but if you look at the shifter location it would be in the dash of the Rx7, you'd have to build a linkage system just to use it.

And 1st gear was near useless w/ the T-5 as well.

96Formula6spd

iTrader: (7)

I think a t-5 might be the way to go. Making a linkage could be done. I have people who could fab that up. But I think a t-5 that took easy ***** along with its never going to be launched hard at a drag strip. A bell housing that is sfi could be covered as a safety item. Still looking at gas mileage. May dump the V8 plan for a miata motor. 1.5 hours of track time plus a refuel or go 4 banger and go 2-3 hours. Still looking into it. But with the shifter on the nv3500 being way back if we go v8 its a t-5.