I'm fixing to swap out some drivetrain components and was wanting to know what to expect in terms of my ET. My basic combo is in my signature at the bottom.

1. Remove my slipping Turbo 350 and replace with a built Turbo 400

2. Remove my stock 12 bolt Posi with 3.73's and put in a 12 bolt stuffed with a Moroso Brute Strength posi, Moser axles and 4.10's.

I will probably not swap both out at the same time so I can get some baseline comparisons. However, if the general consensus was that I would see improvements with both then I might go ahead and do them at the same time. Any input is appreciated.

Right now my best 60ft was a 1.82 :( I figure that's where I need to improve (and start tuning...) to get down in the mid 7's.

I guess it depends on how bad the transmission is slipping, from your signature it doesnt appear to be slipping much. Gear change...maybe a tenth or two max. I swapped from a decent th350 and 2800 stall to a th400 with 3500 stall and saw NO improvement, I think the increased hp it takes to run a 400 washed away the increase I would have had with just the converter swap.

at 89mph with only a 7.99, i wouldn't think the trans is slipping much. 89mph in the 1/8mi should be like a 7.50 ET. unless you have a first gear clutch problem or something. without knowing what cam, intake, carb, etc it will be hard to make a guess at how much the gears will help. if it's pretty mild and doesn't make power past 5500rpms then i'd say the gears wouldn't help a bit.

This past sunday I made 5 passes between 7.62-7.71 @ 89.82-90.72mph, all varied with 60 ft times of 1.70-1.74. My best ever 1/8th time is 7.47@91.68

rapid, what signifies that the trans isn't slipping much? The tranny was REAL sloppy and delayed shifting from 1st to 2nd gear.

m71, Perf RPM intake, closed chambered ovals with big valves, port and chamber work, isky solid flat tappet .560/.560 250@.050 cam, 750DP, 3000 stall.

On my best pass I shifted around 6000 RPM's or so. It was hard to tell because of the delay in the 1 to 2 shift. I was going thru the traps at 88-89mph about 6000-6200 RPM's in 2nd gear.

With your performance numbers it doesnt seem that your trans is slipping much at all, it probably just needs a shift kit. I like B&M in a th350,but that will open a can of worms :D because they shift pretty harsh. What are your 60ft times?

i put a shift kit in it because of the delayed shifting, it didn't help at all. 60ft's ranged from 1.82-1.88. no wheel hop and decent weight transfer. I probably need to upgrade my converter when I swap the tranny. I'll try to dom some research.

Does that sound right, 6000-6200 RPM's in 2nd gear going 88-89mph?

I shift to 3rd right at the 1/8th mile stripe or just before it at 6000 rpm with 28" tires. Get it to hook w/low 1.7x 60 ft. times and you'd be running with me or pretty close.

yeah, I tried to shift right before the stripe a couple of times but didn't help. I forgot to mention that I'm running a 28" DR. I've got a set of 26" slicks that I'll try next time out too. I'd be happy to pull some times down similar to yours. graemlins/thumbsup.gif what's your 1/8th mile incrementals?

My all time best is : 1.66--4.818--7.47--91.68--best last weekend was: 1.70--4.91--7.62--90.72--