anyone with a t-5 and 373's what rpm are you turning at 70 in 5th, and how good is the acceleration

 

With 26 inch tall tires at 70 mph you'll be around 2300-2500 rpm. As for acceleration it's great. I'm pretty sure that there are differant 1st gear ratios for T-5's, depending on what the original rear ratio was. I think richmond gears web site might have a RPM calculator if you want exact RPM


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86 Z-28
350 Carb
2004R
Jegs torque arm
3:73 posi
SOON TO INSTALL T-5

 

B Buss

thanks, I'm pretty much doing what your doing except my trans am is a 82 with the turbo 200 3spd metric trans, I also have a 84 trans am that I'm parting out with the ws-6 suspension 373 posi disc brake rear end, so I'm going to take all the good stuff and throw it in my 82 trans am, I'm just kinda up in the air on what induction system to use I have both versions of tpi and a crossfire system

 

my suggestion, if you have 3.73's, and a t-5, then use the cfi, it's a real high rpm screamer! and will work great with that combo.


btw, wanna sell me the guage cluster and cover, from the 84? I have an 83 bird I'm building for my sister that needs a real guage cluster instead of the base model speedo and gas guage junk.

 

Spoken like someone who has never even driven one!!!! Let alone looked at the intake ports, and noticed that the runners in the intake are only anout 60% as tall as the runners in the heads. If there's any one thing the CFI is poor at, it's high-RPM flow.

If you have the good V8 T-5 with the 2.95 1st gear and .73 5th, the RPMs will be at about 3400 in 4th at 70, and 2450 in 5th.

The acceleration in my car is somewhat anemic, it has a 305 in it; it's not much faster up through the gears than a stock TPI 350. Pretty lame. I hope to have the 305's problems fixed soon. Your results may vary.

 

You could alos have th T-5 with .63 5th, which would result in lower RPM at cruise in 5th, the WCT-5 was the .7X and the nonWC had th .63.

The nonWCT-5 came in everything

The WCT-5 came in th 87+ TPI cars

 

It's not a question of "World Class" vs. the 1st design. The only T-5s I would ever even consider buying even before the 2nd design came out, was the ones that had the .73 5th. The one in my 83 came with the .73 as did every other core I've ever bought. And, the 2nd design ones that come in L03 cars, for CAFE reasons, have the poorer gear. So it's definitely not true that the 1st design all had the inferior CAFE gear and the 2nd design have the better one.

 

i have the 2.95 first and .63 overdrive v8 t5 in my car with 4.11 gears
and let me tell you its awsome! at 55-60 im turning about 2100 rpms with about a 25 inch tall tire. Its launch will snap your head back.

 

hmmm.... I've HAVE owned a cfi car AND i HAVE SEEN THE PORTS and the only thing is was good at was high rpm's and if it had 3.73's it would have been awesome especially if the intake had been ported. I've done alot of reasearch into cfi.

 

CFI is elephant dung. If there's any one thing CFI absolutely has none of, it's high-RPM flow. Even TPI, as pitiful as it is, has more top end than CFI. That's why CFI is so slow to begin with, is the total lack of flow. It drives like a Celebrity, only twice as much of it, is how I describe it, and have since 1982. In 1982 I got back in my paid-for no-top-end-whatsoever 79 Z28 4-speed and left the CFI cars sitting on the lots because they were so completely without nads. The L69, on the other hand, had a BIG top end by comparison with either the anemic 882-equipped L48, or the CFI, or the LG4. A L69 car would absolutely blow a CFI car off the road; the L69 drove like it had 100 more cubic inches, no matter what the "ratings" are. That's why I didn't buy a LU5 car, I got disappointed and then I bought a L69 instead of a LU5 car.

I hate to have to say this so often, but I don't have to resort to reading books, or listening to old timers talk about their {gasp} 20-year old cars! why that's almost an antique! I was there, and I was already a long way from brand-new to hot-rodding by then.

My late little brother was working at Racing Head Service in Memphis at the time, at one of their stores. Some rich kid came in with a CFI car, and wanted an intake, air cleaner, carb, shift kit, blah blah blah done to it. That night after the store closed, we all stood around that intake turned upside-down and laughed, and wondered how people at GM could possibly sleep at night after duping people into paying extra to get that. Those runners, over their full 12" or so of length, couldn't even be ported out to the size of a weenie stock 267 2-barrel intake even if you could find a grinding point that long, because there's no metal; the last inch or so where they added metal to build them up to head size could maybe gasket-match to a set of 416s, but that's about all the metal there is.

Go put one on a chassis dyno and watch the engine's output just crater at 4000 RPM. That setup doesn't even have any mid-range, let alone top end horsepower.

 

Yea, i agree 100% with RB because if the CFI is anything like the L48 (which is in my car at the moment) it doesn't have $hit for top end... the L48 i have, which is out of a '79 Z28, which i think is exactly what RB had, is done breathing by 4500 rpms, but the L69 that was in the car before the 350 (and will also be replacing the 350 because its better) had a MASSIVE top end... that L69 motor will just keep revving untill it blows up. When I had the L69 in my car, all you had to do was drop the loud pedal to the floor and it would be well over 5500 rpm in no time... could probably even wind out faster than most high revving imports i've driven... and that is amazingly good, but the 350 has a REALLY hard time getting past even 4500, and it'd in much better shape than the L69 was when it came out.. I doubt the CFI problem is any different from the breathing problems my 350 has.

 

The huge lack of top end HP I bet is also the main reason that the early C4 corvettes that had CFI usually had really steep gears.. like the 2.64 axle gear in my uncle's Corvette. It would be pointless to drop in a set of 3.73s because it doesn't have the top end power to make use of them, but the HO cars with the L69 motors did get the 3.73 gears because of the massive top end power they had, so they put the really short gears to good use.