Total Bolt In Astro T5 OD Trans (250 I6) All GM Off the Shelf Parts-1965 C10 SBSS

[mixermike]

Hey Sharps, I know I am not the only one who appreciates all the work you have done on this. I was on the fence with this project but am now ready to go forward, so I'm on the lookout for a T5....you sir are an asset to this forum...thank you

[Sharps40]

Cool. Whatevet T5 ya get. Post up the process!

[gulfcoast66]

Great work Sharps40, a lot of info and parts# I also was thinking of going t-5 but wasn't sure of what all it took to get it done ... Thanks for the write-up and part#s. Chris..

[Sharps40]

Great. Now we know there are 2 ways to go w/o heavy mods to truck or trans.

[Sharps40]

Well, looks like a 25 tooth speedometer driven gear is a no go. Jegs just updated that its unavailable and no date known. Thanks for not tellin me when ya called the first time to let me know it would be a week late......

So, I ordered a 24 tooth from Summit. Its in stock and I just get the email that it will arrive in January!!!!!

What the hell is up with speedometer driven gears? Even the local tranny shop don't have any/can't get em.

Oh well, Summit is the last shot. If they can't ship on I spose I'll have to pop for a ratio reducer....ouch...that's another $75 better spent on beer.

[Old Bleu]

Rich, if Summit doesn't have it, let me know before you shell out the big bucks for an adapter. I can check with the transmission shop that got mine. He had it in a couple hours, so it must have been available locally. That is unless he just had some on hand...

[Sharps40]

Hell if they got one I want it 24 or 25 teeth. I can always canx orders or return em .... at this point it seems nothing is comin my way in less than about 4 weeks time! Lemmie know how much and a shipping address and I'll have money order headin yer way in no time flat.

[Sharps40]

Just got the email from summit, the 24 toot is backordered till 2 jan 14 which means.....it prolly aint' comeing. So if ya can find me a 24 or 25 tooth gear for a T5, I'll take it......thanks in advance Ol Bleu, either way!

[Old Bleu]

OK, I'll run over there tomorrow at lunchtime and see what he says. Will let you know. As I recall, he wanted to get a 25 tooth for mine, but could only get a 24 tooth.

[Sharps40]

Thanks. 24 is da bomb!!!

[Old Bleu]

PM sent

[Sharps40]

Got it. Thanks Bleu! 24 teeth is better than 20 and way better than West Virginia which has no teeth at all!

[Old Bleu]

Got the gear and sent you a PM!

[Sharps40]

You my friend are the most effective and speedy parts man in the entire south east!!!!!!

Thanks!

[Old Bleu]

Glad that I could help. I've learned so much from your posts and pictures that it was the least that I could do.

[NavyChief]

Sharps, been quietly following the thread. I have a 69 with the 250 and was thinking of the T5 upgrade. First I may have to replace the engine though as mine is getting pretty worn out. How do you like your from O’Reilly’s? Is it purring good?

[Sharps40]

Purring good. Still playin with the tune...mostly waitin for it to break in a bit and I'll put a wide band O2 on it to get serious with tuning. But 17 degrees advance and pulls well/no ping. We are using mid and high grade gas now...no more 87 octane around here.

Engine came with the valves screwed down flat so had to loosen em up to let em pump up then adjust a couple times. Also, going back in for a leaky rear main seal. Shop says crate motors often come with the rear main installed upside down and as a consequence they weep oil. So far so good.

Its a bare long block from oreillies. You'll need all your tins from the old motor and a waterpump too.

17.5 mpg out of the box and we're not doing any serious tuning or even got the motor broken in beyond about 1500 miles yet.

[Sharps40]

The oriellies motor carries an ATK part number. I strongly believe its an ATK build.

[Sharps40]

I used a DC76 engine which is the 1975-1979 non integrated head engine.

You could also dry a DC74 engine which is 1968-1972.

[NavyChief]

Yea the crate engine is the way I am leaning as a rebuild here costs an arm and a leg! I can get a crate cheaper and swap it myself hopefully!

[Sharps40]

My crate was $1540 with tax. No core charge, no delivery charge, no take away charge, $200 off the top, $45 in Oreilly coupons cause I signed up for the club card first and free paint and free first oil/filter.

Its good to shop local. Only a local fella can take good care of ya like that.

[tincan1966]

The reason why speedo gears are hard to come by- most vehicles since about 1995 now all have electric speedos.

[Sharps40]

So, what changed? Cables and 1000 turns per mile worked for lotsa years? Certaintly it ain't cheeper to go to electric senders (which us-a damnable set o gears tooo!). Was it cause some sorta signal is needed for the computer that micromanages engine function?

[tincan1966]

Yes, after about 1995 most ECM's need a signal to calculate vehicle speed to control transmission shifts points, converter lockup and cruise control. A lot of the mfg's use a "flying magnet" type sensor that generate as much as 2000-4000 pulses per revolution. Also by taking a vehicle speed reading and them information from the MAP sensor, the ECM can determine engine load and adjust timing and fuel enrichment as needed. it does this several times per second.

I personally, prefer an electric speedo. Takes about 15 minutes to calibrate one and it doesn't care about rear gears, tire size, etc.

The ECM in my '65 daily driver reads the speedo to control the converter lockup. I have a pulse generator adapter between the trans gear and the OEM speedo cable. My speedo is about 10MPH fast with the 350C trans, 3.73 gears and 265/70/15 tires. But I am changing the gauges soon, so no sense in playing with the gears, as I will be eliminating the cable all together.

[tincan1966]

Originally Posted by Sharps40

So, what changed? Cables and 1000 turns per mile worked for lotsa years? Certaintly it ain't cheeper to go to electric senders (which us-a damnable set o gears tooo!). Was it cause some sorta signal is needed for the computer that micromanages engine function?

LOL You can call it micromanagement, if you want, but I don't have to spend days/weeks, fiddling/adjusting a carb and timing to get 15 mpg, or trying to get the power curve I want.
I average 17 mpg with almost all in town driving, and that's with a tired 305 with about 245K on it with nothing more than consistent oil changes, routine maintenance, & ethanol free fuel. The only performance items I have are short tube headers, MSD ignition wires and NGK V power spark plugs.