Posi units worth........priceless........

[wild one]

Or a half of a second reduction in E.T. ! I just returned home after an afternoon of test and tune drag racin' at Sacramento Raceway. I was able to literally shave .51 of a second off of my previous best run of 16.15 seconds, my new best E.T. is 15.64 seconds. Most (if not all) of the gain was due to my much improved 60 ft time - it went from 2.4? seconds to 2.09 seconds. My mph did drop off some, from 91.38 to 86.27 but I suspect that is due in part to recent changes to the truck to make it a little more civilized.

When I installed the posi, I changed from 3.73's to 3.40's to help drop the RPM some for better freeway driving and I added power steering to help with parking lot maneuvers (now my wife CAN physically drive the truck). This makes it easier to justify spending some $ on it since it is now the 2nd automatic vehicle in our fleet of 6 cars/trucks and she refuses to drive a manual. That plus the truck was an absolute pig to try to steer in tight spaces.

Now, I realize that these are not stellar numbers compared to any other postings of late but the truck is improving none the less. I have gone much quicker and faster in the quarter in some of my other vehicles but none the less it was fun seeing what can be squeezed out of "recycled" parts on a shoestring budget.

While I was at the track I had the opportunity to meet a fellow board member, he goes by the name COUCH and pilots a primered black 69 stepside - nice guy with a rather unassuming looking ride. Unassuming that is until he ripped off a LOW 12 second run with a moderately warmed over 350 and a large dose of N2O - very impressive. All in all it was a good day spent with some friends doing one of my favorite aspects of this hobby - Drag Racing!

[chevy72blu]

Awsome!!! I remember back when I put my Auburn in... Similar change in ET. Sounds like my old combo was nearly identical to yours. Lemme guess... 350 with slightly modifed heads (or TBI's?), 270-274ish hyd flat tappet grind, 9.5 or so CR, aftermarket intake/carb?

Those ET's and trap were near identical to mine on hot days at 2200 ft above sea level. Although, in CA I'd bet you are much lower.

Glad to hear you had fun with it at the track. Damn I miss it... F*#%in summer classes...

[SRH916]

where did you pick up your posi from, and about how much did it set you back? I am in sacramento, and have been looking for a place to get one for a while. for taking some time off the line, but for me more getting both tires to spin

[wild one]

Originally Posted by chevy72blu

Lemme guess... 350 with slightly modifed heads (or TBI's?), 270-274ish hyd flat tappet grind, 9.5 or so CR, aftermarket intake/carb?

Those ET's and trap were near identical to mine on hot days at 2200 ft above sea level. Although, in CA I'd bet you are much lower.

Actually, the engine is a 400 sb and is bone stock carb to oil pan. It came out of a 1975 Impala and is backed by the donor cars stock TH350 transmission. I think the biggest difference is elevation and displacement... the track I raced at is 30 feet above sea level, and my engine is 50 cubic inches larger.

As far as the posi unit goes, I purchased mine at the local Pick N' Pull for $40.00 then rebuilt it with new clutches, plates and springs for an additional $150.00. The ring and pinion came from my 1975 parts truck, the rear housing and axles from a 1971 C10, and a new master rebuild kit (bearings, shims, seals, etc...). My total amount invested was around $400.00.

Thanks for the props, more mods to come to the ol' bread truck.

[chevy72blu]

Originally Posted by wild one

Actually, the engine is a 400 sb and is bone stock carb to oil pan. It came out of a 1975 Impala and is backed by the donor cars stock TH350 transmission. I think the biggest difference is elevation and displacement... the track I raced at is 30 feet above sea level, and my engine is 50 cubic inches larger.

I gotcha - that makes sense. They were just so similar that I wanted to try to hit the nail on the head. I suppose I should have looked at your sig... lol.

I thought about building a roller 400 before I built my BBC... Then I found such a killer deal on a nearly virgin 454 block that I couldnt turn it down. What are your plans with it to improve on your ET? Or, are you going to just race it as it is?