I got a vortec 383 with the following:
vortec heads with beehive springs
comp cams 276hr 224 230 duration 536 544 lift 1.6 rockers
rpm air gap intake
750dp 4779
9.3 compression ratio
36 timing locked out
converter is a 2500 stall
3200 pound camaro

new trans is th350. rear is setup with 3.73 ratio currently. can i get away with a swap to 3.08 to make this more freeway friendly without killing performance? do i have too much camshaft for the 3.08?
87mph 1/8 mile performance with the old th700 trans and the 3.73.

 

I have a 355, 284H cam, and solid valve train, and the rest is about the same as yours. (no stall though).

I think it would kill a bit of performance on the drag strip, but you wont really notice on the street.

3.42 might be a better choice. However, im questioning how much you are willing to sacrifice. Your combo sure is built to have fun, but if youre worried about gas mileage, and driveability, the 3.08 might be alright.

Sorry i cant give you a definative answer, but 3.73 to 3.08 is definately a big jump.

 

not worried at all about economy. the revs are up too much on the freeway at 65mph. the exhaust is loud at these revs. a 3.42 really would not change things much in that reguard. choices.... humm.....

 

Oh i c. Normally the answer would be easy, YES you would loose alot of power. BUT im stumped on the stall part.

Basically if youre worried about 1/4 mile times, see what kind of mph you would get if you went to a 3.08.

I think u MIGHT be able to get the best of both worlds, because of the stall. Because youd launch close to your power band, the 383 is a stroker, so you have plenty of torque, and 3.08 would wind down the revs a bit.

You may wanna wait for someone else to chime in too, as my experience is limited.

 

anybody else been in this type of situation? advice? the th350 is staying.

 

I kinda have to agree that 3.42's would probably be your best bet. Unfortunately, when it comes to the 12 bolt rear, the aftermarket doesn't supply a whole lot of choices for 3 series ratios. GM originally offered a 3.31 gearset, and that'd probably be about perfect for yours. I have a feeling the 3.08's would hurt your takeoff too much, considering the TH350's 1st gear is only 2.52:1. If you didn't mind the risk of trying a set of used gears, I'd suggest putting some original GM 3.31's in. Otherwise, if you're going new, I'd have to say 3.42's. As a matter of fact, I have 3.73's in my 69 Camaro's 12 bolt at the moment, and I'm in the process of setting up my spare 12 bolt with Motive 3.42's as I type this. I'm doing it for the same reason. My rpms are pretty high on the freeway too. 3.42's may not be a big drop, but it should help some, while not hindering performance too bad. Btw, with the 3.73's, I can shift into 4th gear around 30-35 mph when I'm driving easy. Lol.

 

I agree the 3.31 gear is a great idea. I had no clue of that ratio. where can i get some? Only used ones?

 

Yeah, I'm pretty sure you can only get them used. I've never seen them available from any aftermarket suppliers. Guess they figured 3.42 is close enough, so why bother with the 3.31's. That was the original ratio in my 69 Camaro's 12 bolt before I changed it to 3.73. They really weren't too bad, even with a 4 speed manual. I see used sets of them pop up on ebay quite often. If you check on there every few days, you should be able to get a set fairly easily. If you're really lucky, you may even find a NOS set of them. It was a pretty common ratio in the early Camaros and Chevelles, and a lot of guys end up ditching them in favor of 3.73's or 4.10's. Of course I run a Muncie M20, which has the same 2.52:1 1st gear as your TH350. With the M21 or M22, 4.10 is really the starting point since 1st gear is only 2.20:1. I tried using a M21 with my 3.73's and it was a total dog off the line!

 

Its been a while and i am still tired of the rpm with the 3.73 (3000rpm at 61mph). I have a access to a set of 3.08 and 3.42 gears. One set is going in. My appt. To install is may 7th. I have been crunching numbers for a couple days and it seems the 3.08 ring and pinion is going to be about right for crusing around backroads and the highway. 2500 at 65 with my 27inch tire seems perfect.

I realize the 7.76 first gear is not ideal but i cant have my cake and eat it too. I Tried that overdrive trans and failed i am not going back.
The rpm just plain sucks with the 3.73. I figure the motor is a stroker, complemented with a mild camshaft and the 2500 stall i should be alright if i dont stab it totally from a dig.
I would Use the 3.42 but the highway revs are still too high. Plus the mpg has taken a toll for the worse and it will be nice to get some back.